cmd/go: clean up installHeader action
cmd/go: clean up installHeader action

This was confusing when I was trying to fix go build -o.
Perhaps due to that fix, this can now be simplified from
three functions to one.

Change-Id: I878a6d243b14132a631e7c62a3bb6d101bc243ea
Reviewed-on: https://go-review.googlesource.com/13027
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

joshsammut/go,Badredapple/go,jonasi/go,leeric92/go,roth1002/go,dafyddcrosby/go,g522342435/go,ichu501/go,goodlang/good,Samurais/go,zcwfeng/go,WIZARD-CXY/go,qskycolor/go,danielsoro/go,CAFxX/go,mwhudson/go,jacobsa/go,XuYunnan/go,Badredapple/go,codestation/go,nakedgc/go,vishsingh/go,CAFxX/go,codestation/go,willjunspecial/go,cainiaocome/go,mbrukman/go,Young55555/go,arschles/go-1,Stan-Lin-/go,NunoEdgarGub1/go,Pulgafree/go,binarycrusader/go,jasonxiong/go,roth1002/go,honsiorovskyi/go,linux-on-ibm-z/go,andrewchambers/go,donnel6809/go,gdey/go,kim-racktop/go,xiuzhifu/go,devpadawan/go,XuYunnan/go,Charlesdong/go-1,jacobsa/go,gdey/go,goodlang/good,honsiorovskyi/go,skatsuta/go,cookerzhu/go,alash3al/go,beealone/go,zouchao2010/go,kevinc0825/go,ErikDubbelboer/go,ObjectiveJoe/go,mikekap/go,AALEKH/go,springning/go,NichoZhang/go,Young55555/go,WIZARD-CXY/go,Jordanzuo/go,rentongzhang/go,jdeng/go,4ad/go,yuhengye/go,arschles/golang-go,andrewchambers/go,mgyenik/go,mbrukman/go,AALEKH/go,Badredapple/go,vishsingh/go,CiscoCloud/go,codestation/go,linux-on-ibm-z/go,nakedgc/go,deft-code/go,xiuzhifu/go,rentongzhang/go,jefby/go,yuhengye/go,Cofyc/go,suncycheng/go,roth1002/go,GeorgiCodes/go,cloudflare/go,mdp/go,kim-racktop/go,constantine001/go,sosop/go,nawawi/go,XuYunnan/go,ichu501/go,chinanjjohn2012/go,linux-on-ibm-z/go,g522342435/go,zouchao2010/go,Jordanzuo/go,dterei/go,ImJasonH/go,Endika/go,kevinc0825/go,cloudflare/go,myPublicGit/go,kim-racktop/go,cyberroadie/go,constantine001/go,ImJasonH/go,vishsingh/go,jacobhaven/go,ErikDubbelboer/go,NichoZhang/go,parkdy/go,samanalysis/go,josharian/go,xiuzhifu/go,miolini/go,uileyar/go,famorted/go,joshsammut/go,sndnvaps/go,CodyGuo/go,leeric92/go,nawawi/go,beealone/go,cloudflare/go,likesea/go,ichu501/go,cainiaocome/go,jdeng/go,deft-code/go,monetate/go,Endika/go,ifagnosticism/go,springning/go,derekmarcotte/go,myPublicGit/go,jdhenke/go,cloudflare/go,myPublicGit/go,sinuos/go,polyverse-security/go,jameskumar/go,sosop/go,willjunspecial/go,josharian/go,sosop/go,gdey/go,ganboing/go-esx,miolini/go,jdeng/go,CodyGuo/go,kim-racktop/go,Charlesdong/go-1,AALEKH/go,mdp/go,cookerzhu/go,XuYunnan/go,theif519/go,malvira/go,ImJasonH/go,momchil-velikov/go,alex-zhang/go,kevinc0825/go,rentongzhang/go,nakedgc/go,jefby/go,ifagnosticism/go,danycoro/go,Jordanzuo/go,undergrowthlinear/go,mbrukman/go,jdhenke/go,greyhwndz/go,jonathanmarvens/go,jacobxk/go,vanloswang/go,mgyenik/go,deft-code/go,XuYunnan/go,willjunspecial/go,NunoEdgarGub1/go,jonahglover/go,undergrowthlinear/go,samanalysis/go,jonasi/go,jacobxk/go,parkdy/go,joshsammut/go,myPublicGit/go,mwhudson/go,WIZARD-CXY/go,albertjin/golang-go,mgyenik/go,malvira/go,CAFxX/go,odeke-em/go,fjballest/golang,ErikDubbelboer/go,g522342435/go,monetate/go,fjballest/golang,zcwfeng/go,undergrowthlinear/go,WIZARD-CXY/go,JioCloud/go,dafyddcrosby/go,Stan-Lin-/go,theass/go,wangfakang/go-1,kakuhiroshi/go,miolini/go,ichu501/go,Badredapple/go,linux-on-ibm-z/go,albertjin/golang-go,uileyar/go,devpadawan/go,golang/go,dpatel06/go,roth1002/go,Cofyc/go,Charlesdong/go-1,constantine001/go,slavau/go,mgyenik/go,jmptrader/go,vishsingh/go,rentongzhang/go,vsdutka/go,jasonxiong/go,gdey/go,mbrukman/go,Samurais/go,odeke-em/go,GeorgiCodes/go,Stan-Lin-/go,chinanjjohn2012/go,sndnvaps/go,famorted/go,beealone/go,jefby/go,ImJasonH/go,wangfakang/go-1,suncycheng/go,jacobxk/go,jonathanmarvens/go,malvira/go,mbrukman/go,derekmarcotte/go,linux-on-ibm-z/go,ericsnowcurrently/go,zcwfeng/go,kevinc0825/go,chinanjjohn2012/go,zcwfeng/go,mikekap/go,momchil-velikov/go,akutz/go,shines77/go,zouchao2010/go,uileyar/go,honsiorovskyi/go,jonasi/go,CiscoCloud/go,arschles/golang-go,polyverse-security/go,rentongzhang/go,chinanjjohn2012/go,zouchao2010/go,yasarkunduz/go,snowsnail/go,qskycolor/go,derekmarcotte/go,Jordanzuo/go,joshsammut/go,albertjin/golang-go,vishsingh/go,Stan-Lin-/go,deft-code/go,ObjectiveJoe/go,suncycheng/go,theass/go,malvira/go,donnel6809/go,chinanjjohn2012/go,ifagnosticism/go,NichoZhang/go,CodyGuo/go,lihuanghai/go,springning/go,sndnvaps/go,ObjectiveJoe/go,xujianhai/go,joshsammut/go,GeorgiCodes/go,vsekhar/elastic-go,g522342435/go,NichoZhang/go,myPublicGit/go,roth1002/go,rentongzhang/go,polyverse-security/go,roth1002/go,AALEKH/go,ganboing/go-esx,constantine001/go,devpadawan/go,shines77/go,arschles/go-1,miolini/go,slavau/go,mgyenik/go,vsdutka/go,ObjectiveJoe/go,yuhengye/go,g522342435/go,sndnvaps/go,beealone/go,ganboing/go-esx,alex-zhang/go,samanalysis/go,cainiaocome/go,mbrukman/go,yasarkunduz/go,cloudflare/go,cyberroadie/go,golang/go,jefby/go,jasonxiong/go,zcwfeng/go,Pulgafree/go,suncycheng/go,slavau/go,Jordanzuo/go,zcwfeng/go,mdp/go,jacobxk/go,danielsoro/go,golang/go,momchil-velikov/go,CodyGuo/go,lihuanghai/go,danycoro/go,xujianhai/go,danycoro/go,vsekhar/elastic-go,josharian/go,zouchao2010/go,alash3al/go,dterei/go,jacobxk/go,devpadawan/go,polyverse-security/go,jameskumar/go,shines77/go,NunoEdgarGub1/go,XuYunnan/go,greyhwndz/go,lihuanghai/go,snowsnail/go,skatsuta/go,NichoZhang/go,JioCloud/go,roth1002/go,Badredapple/go,mikekap/go,lihuanghai/go,jdhenke/go,yasarkunduz/go,JioCloud/go,JioCloud/go,Stan-Lin-/go,malvira/go,polyverse-security/go,jdeng/go,devpadawan/go,greyhwndz/go,vsekhar/elastic-go,Endika/go,samanalysis/go,derekmarcotte/go,alex-zhang/go,goodlang/good,lihuanghai/go,xujianhai/go,skotti/go,cyberroadie/go,odeke-em/go,binarycrusader/go,xiuzhifu/go,jonahglover/go,willjunspecial/go,skotti/go,kakuhiroshi/go,sosop/go,jefby/go,deft-code/go,kim-racktop/go,fjballest/golang,donnel6809/go,undergrowthlinear/go,XuYunnan/go,CarterTsai/go,stormltf/go,Cofyc/go,slavau/go,4ad/go,slavau/go,zhangg/go,jameskumar/go,skotti/go,jasonxiong/go,sinuos/go,joshsammut/go,yasarkunduz/go,jacobhaven/go,danycoro/go,jdhenke/go,sosop/go,CarterTsai/go,XuYunnan/go,cyberroadie/go,xiuzhifu/go,lihuanghai/go,odeke-em/go,xujianhai/go,ErikDubbelboer/go,g522342435/go,devpadawan/go,CiscoCloud/go,jdhenke/go,b54898533/go,gdey/go,andrewchambers/go,greyhwndz/go,linux-on-ibm-z/go,willjunspecial/go,snowsnail/go,samanalysis/go,CodyGuo/go,dpatel06/go,ErikDubbelboer/go,Pulgafree/go,mwhudson/go,xiaobodu/go,Endika/go,shines77/go,GeorgiCodes/go,danielsoro/go,undergrowthlinear/go,uileyar/go,stormltf/go,gdey/go,arschles/go-1,monetate/go,xujianhai/go,chinanjjohn2012/go,greyhwndz/go,springning/go,cainiaocome/go,jacobsa/go,Badredapple/go,springning/go,ObjectiveJoe/go,Jordanzuo/go,goodlang/good,sinuos/go,4ad/go,NichoZhang/go,likesea/go,jonasi/go,xiaobodu/go,jonahglover/go,vsdutka/go,goodlang/good,stormltf/go,CAFxX/go,nakedgc/go,danycoro/go,CarterTsai/go,zouchao2010/go,mwhudson/go,binarycrusader/go,theass/go,greyhwndz/go,jacobsa/go,jameskumar/go,b54898533/go,theass/go,undergrowthlinear/go,likesea/go,qskycolor/go,Samurais/go,Endika/go,odeke-em/go,4ad/go,jasonxiong/go,kakuhiroshi/go,skatsuta/go,jacobsa/go,ganboing/go-esx,danielsoro/go,binarycrusader/go,theif519/go,miolini/go,Young55555/go,theif519/go,monetate/go,Charlesdong/go-1,dafyddcrosby/go,kakuhiroshi/go,jefby/go,dafyddcrosby/go,zouchao2010/go,shines77/go,WIZARD-CXY/go,Pulgafree/go,leeric92/go,rachtsingh/gogojuice,ericsnowcurrently/go,xiaobodu/go,zhangg/go,arschles/golang-go,NichoZhang/go,dterei/go,nakedgc/go,kevinc0825/go,alex-zhang/go,Jordanzuo/go,sosop/go,vishsingh/go,mgyenik/go,ObjectiveJoe/go,jmptrader/go,yasarkunduz/go,yuhengye/go,codestation/go,andrewchambers/go,sinuos/go,jonathanmarvens/go,uileyar/go,ifagnosticism/go,binarycrusader/go,Charlesdong/go-1,codestation/go,mikekap/go,sinuos/go,jmptrader/go,zhangg/go,jasonxiong/go,yasarkunduz/go,ErikDubbelboer/go,snowsnail/go,theass/go,xujianhai/go,vsdutka/go,yuhengye/go,dpatel06/go,chinanjjohn2012/go,snowsnail/go,suncycheng/go,vanloswang/go,CodyGuo/go,jameskumar/go,fjballest/golang,skatsuta/go,albertjin/golang-go,wangfakang/go-1,rentongzhang/go,vsdutka/go,suncycheng/go,zcwfeng/go,famorted/go,wangfakang/go-1,alash3al/go,josharian/go,WIZARD-CXY/go,Cofyc/go,akutz/go,monetate/go,GeorgiCodes/go,theass/go,jonasi/go,nawawi/go,Endika/go,vanloswang/go,jonahglover/go,deft-code/go,uileyar/go,kakuhiroshi/go,NunoEdgarGub1/go,b54898533/go,jonahglover/go,qskycolor/go,deft-code/go,joshsammut/go,CodyGuo/go,willjunspecial/go,yangzhongj/go,sinuos/go,alex-zhang/go,yangzhongj/go,albertjin/golang-go,momchil-velikov/go,leeric92/go,momchil-velikov/go,arschles/golang-go,binarycrusader/go,vsdutka/go,springning/go,jdeng/go,jmptrader/go,wangfakang/go-1,cookerzhu/go,jacobhaven/go,mdp/go,Cofyc/go,jonathanmarvens/go,xiuzhifu/go,binarycrusader/go,jonasi/go,josharian/go,sndnvaps/go,mikekap/go,Pulgafree/go,g522342435/go,vanloswang/go,myPublicGit/go,rachtsingh/gogojuice,beealone/go,theass/go,nawawi/go,ichu501/go,mbrukman/go,dterei/go,golang/go,malvira/go,donnel6809/go,jonathanmarvens/go,theif519/go,ifagnosticism/go,kim-racktop/go,vsekhar/elastic-go,devpadawan/go,shines77/go,golang/go,derekmarcotte/go,CiscoCloud/go,jacobhaven/go,cookerzhu/go,jefby/go,xiaobodu/go,mdp/go,snowsnail/go,slavau/go,josharian/go,akutz/go,dafyddcrosby/go,AALEKH/go,constantine001/go,kakuhiroshi/go,wangfakang/go-1,donnel6809/go,snowsnail/go,dpatel06/go,dterei/go,Stan-Lin-/go,ImJasonH/go,mdp/go,stormltf/go,codestation/go,NunoEdgarGub1/go,Cofyc/go,Young55555/go,dafyddcrosby/go,sndnvaps/go,vanloswang/go,CarterTsai/go,stormltf/go,golang/go,skatsuta/go,Charlesdong/go-1,Jordanzuo/go,jonathanmarvens/go,parkdy/go,parkdy/go,dafyddcrosby/go,Stan-Lin-/go,arschles/go-1,mwhudson/go,parkdy/go,Young55555/go,jdeng/go,ifagnosticism/go,malvira/go,albertjin/golang-go,sndnvaps/go,shines77/go,yuhengye/go,miolini/go,albertjin/golang-go,jacobsa/go,vishsingh/go,arschles/golang-go,CiscoCloud/go,mwhudson/go,jacobxk/go,willjunspecial/go,rachtsingh/gogojuice,CAFxX/go,mwhudson/go,NunoEdgarGub1/go,rachtsingh/gogojuice,theass/go,malvira/go,CAFxX/go,skatsuta/go,cainiaocome/go,josharian/go,fjballest/golang,akutz/go,suncycheng/go,monetate/go,jacobhaven/go,ImJasonH/go,famorted/go,slavau/go,springning/go,deft-code/go,Pulgafree/go,jdeng/go,goodlang/good,codestation/go,kevinc0825/go,ErikDubbelboer/go,jacobhaven/go,GeorgiCodes/go,vanloswang/go,famorted/go,jefby/go,goodlang/good,golang/go,donnel6809/go,qskycolor/go,mgyenik/go,skotti/go,xujianhai/go,mikekap/go,jacobsa/go,4ad/go,vsekhar/elastic-go,JioCloud/go,cookerzhu/go,CiscoCloud/go,JioCloud/go,ericsnowcurrently/go,fjballest/golang,cyberroadie/go,ericsnowcurrently/go,polyverse-security/go,wangfakang/go-1,cyberroadie/go,codestation/go,CarterTsai/go,famorted/go,alash3al/go,nawawi/go,xiaobodu/go,xiaobodu/go,cookerzhu/go,ifagnosticism/go,zhangg/go,sinuos/go,WIZARD-CXY/go,ErikDubbelboer/go,sndnvaps/go,devpadawan/go,nawawi/go,Cofyc/go,qskycolor/go,mbrukman/go,vsdutka/go,ganboing/go-esx,Young55555/go,yasarkunduz/go,AALEKH/go,Endika/go,jonahglover/go,mgyenik/go,vanloswang/go,jdhenke/go,ichu501/go,ichu501/go,ObjectiveJoe/go,dterei/go,derekmarcotte/go,dterei/go,rachtsingh/gogojuice,lihuanghai/go,mikekap/go,danycoro/go,danielsoro/go,likesea/go,jonasi/go,momchil-velikov/go,linux-on-ibm-z/go,Pulgafree/go,CAFxX/go,stormltf/go,cainiaocome/go,CarterTsai/go,jonasi/go,honsiorovskyi/go,odeke-em/go,theif519/go,dpatel06/go,ImJasonH/go,rachtsingh/gogojuice,cyberroadie/go,NichoZhang/go,ganboing/go-esx,vsekhar/elastic-go,nawawi/go,snowsnail/go,slavau/go,wangfakang/go-1,mikekap/go,linux-on-ibm-z/go,likesea/go,chinanjjohn2012/go,nawawi/go,leeric92/go,4ad/go,yangzhongj/go,jacobsa/go,momchil-velikov/go,famorted/go,Badredapple/go,ichu501/go,jdhenke/go,samanalysis/go,jasonxiong/go,akutz/go,vsdutka/go,donnel6809/go,jameskumar/go,CiscoCloud/go,xujianhai/go,ericsnowcurrently/go,odeke-em/go,arschles/go-1,christopher-henderson/Go,cookerzhu/go,rachtsingh/gogojuice,stormltf/go,constantine001/go,kevinc0825/go,CodyGuo/go,ifagnosticism/go,jacobxk/go,jdeng/go,constantine001/go,joshsammut/go,alash3al/go,alex-zhang/go,Charlesdong/go-1,nakedgc/go,jacobhaven/go,alash3al/go,kim-racktop/go,vsekhar/elastic-go,jacobxk/go,skotti/go,alash3al/go,monetate/go,danielsoro/go,skatsuta/go,ericsnowcurrently/go,ericsnowcurrently/go,WIZARD-CXY/go,yuhengye/go,andrewchambers/go,alex-zhang/go,lihuanghai/go,cyberroadie/go,danielsoro/go,JioCloud/go,vishsingh/go,JioCloud/go,andrewchambers/go,Badredapple/go,derekmarcotte/go,kakuhiroshi/go,arschles/golang-go,parkdy/go,albertjin/golang-go,xiaobodu/go,skotti/go,ObjectiveJoe/go,undergrowthlinear/go,4ad/go,rentongzhang/go,Pulgafree/go,qskycolor/go,andrewchambers/go,kim-racktop/go,b54898533/go,jonathanmarvens/go,jasonxiong/go,beealone/go,shines77/go,yuhengye/go,samanalysis/go,mdp/go,cloudflare/go,jmptrader/go,sosop/go,gdey/go,dpatel06/go,dafyddcrosby/go,ImJasonH/go,stormltf/go,momchil-velikov/go,undergrowthlinear/go,ericsnowcurrently/go,greyhwndz/go,myPublicGit/go,GeorgiCodes/go,CarterTsai/go,willjunspecial/go,likesea/go,kakuhiroshi/go,derekmarcotte/go,akutz/go,arschles/go-1,honsiorovskyi/go,greyhwndz/go,Samurais/go,theif519/go,CiscoCloud/go,NunoEdgarGub1/go,miolini/go,Samurais/go,AALEKH/go,parkdy/go,CAFxX/go,nakedgc/go,famorted/go,dpatel06/go,ganboing/go-esx,yangzhongj/go,polyverse-security/go,rachtsingh/gogojuice,NunoEdgarGub1/go,Stan-Lin-/go,springning/go,beealone/go,jmptrader/go,GeorgiCodes/go,Cofyc/go,jameskumar/go,golang/go,josharian/go,jameskumar/go,AALEKH/go,cainiaocome/go,yasarkunduz/go,yangzhongj/go,constantine001/go,skotti/go,theif519/go,arschles/golang-go,Samurais/go,likesea/go,donnel6809/go,g522342435/go,jmptrader/go,samanalysis/go,cookerzhu/go,arschles/golang-go,jonahglover/go,CarterTsai/go,uileyar/go,honsiorovskyi/go,cloudflare/go,alex-zhang/go,skatsuta/go,arschles/go-1,likesea/go,Charlesdong/go-1,b54898533/go,b54898533/go,andrewchambers/go,zhangg/go,vsekhar/elastic-go,cainiaocome/go,leeric92/go,theif519/go,b54898533/go,xiaobodu/go,roth1002/go,fjballest/golang,jacobhaven/go,kevinc0825/go,zhangg/go,leeric92/go,mdp/go,xiuzhifu/go,zhangg/go,zhangg/go,danycoro/go,beealone/go,miolini/go,danielsoro/go,nakedgc/go,vanloswang/go,jdhenke/go,sosop/go,honsiorovskyi/go,mwhudson/go,honsiorovskyi/go,gdey/go,Young55555/go,ganboing/go-esx,binarycrusader/go,fjballest/golang,yangzhongj/go,Samurais/go,polyverse-security/go,odeke-em/go,uileyar/go,zouchao2010/go,akutz/go,myPublicGit/go,xiuzhifu/go,zcwfeng/go,jonahglover/go,jonathanmarvens/go,danycoro/go,Samurais/go,yangzhongj/go,4ad/go,skotti/go,alash3al/go,b54898533/go,leeric92/go,dpatel06/go,dterei/go,Young55555/go,parkdy/go,yangzhongj/go,akutz/go,jmptrader/go,sinuos/go,monetate/go,goodlang/good,suncycheng/go,Endika/go,arschles/go-1,cloudflare/go,qskycolor/go