fix static compile with go 1.4
fix static compile with go 1.4

Signed-off-by: Victor Vieux <ce584ac70734cfa5a848cd28039798932c7ea675@docker.com>

moxiegirl/swarm,shin-/docker.github.io,rav121/swarm,sfsmithcha/swarm,sanscontext/docker.github.io,moxiegirl/swarm,rillig/docker.github.io,anweiss/docker.github.io,sfsmithcha/swarm,bdwill/docker.github.io,ricca742/swarm,Spritekin/swarm,docker/docker.github.io,shin-/docker.github.io,anweiss/docker.github.io,joeuo/docker.github.io,pssahi/swarm,dnephin/swarm,danix800/docker.github.io,shot/swarm,barais/swarm,rillig/docker.github.io,denverdino/denverdino.github.io,gradywang/swarm,aduermael/docker.github.io,denverdino/swarm,bdwill/docker.github.io,parapsyche/swarm,yp-engineering/swarm,doronp/swarm,ezrasilvera/swarm,shin-/docker.github.io,raoofm/swarm,cgvarela/swarm,thaJeztah/docker.github.io,denverdino/docker.github.io,fugr/swarm,BSWANG/swarm,troy0820/docker.github.io,mrjana/swarm,alexisbellido/docker.github.io,gdevillele/docker.github.io,liubin/swarm,atlassian/swarm,iaintshine/swarm,joaofnfernandes/docker.github.io,johnstep/docker.github.io,shin-/docker.github.io,shot/swarm,jeffjen/swarm,morpheyesh/swarm,thaJeztah/docker.github.io,kyhavlov/swarm,rav121/swarm,gonkulator/swarm,BSWANG/denverdino.github.io,shubheksha/docker.github.io,londoncalling/docker.github.io,ejholmes/swarm,atlassian/swarm,docker-zh/docker.github.io,ejholmes/swarm,JimGalasyn/docker.github.io,raoofm/swarm,docker-zh/docker.github.io,shubheksha/docker.github.io,auzias/swarm,docker-zh/docker.github.io,u2mejc/swarm,londoncalling/docker.github.io,danix800/docker.github.io,docker/docker.github.io,joeuo/docker.github.io,BSWANG/swarm,LuisBosquez/docker.github.io,kunalkushwaha/swarm,shubheksha/docker.github.io,rancher/swarm,gdevillele/docker.github.io,tranceitionalMynd/swarm,BSWANG/denverdino.github.io,adouang/swarm,denverdino/docker.github.io,christophelec/swarm,phiroict/docker,rutulpatel/swarm,gradywang/swarm,CodeNow/swarm,BSWANG/denverdino.github.io,FreedomWangLi/swarm,menglingwei/denverdino.github.io,LuisBosquez/docker.github.io,errordeveloper/swarm,therealbill/swarm,jzwlqx/denverdino.github.io,johnstep/docker.github.io,rillig/docker.github.io,tangkun75/swarm,dnephin/swarm,NunoEdgarGub1/swarm,anweiss/docker.github.io,polyverse-security/swarm,troy0820/docker.github.io,thaJeztah/docker.github.io,rutulpatel/swarm,MHBauer/swarm,aduermael/docker.github.io,londoncalling/docker.github.io,menglingwei/denverdino.github.io,Aorjoa/swarm,denverdino/swarm-1,shin-/docker.github.io,liubin/swarm,sanscontext/docker.github.io,joaofnfernandes/docker.github.io,CiaranCostello/swarm,LuisBosquez/docker.github.io,linecheng/swarm,xFragger/swarm,docker/docker.github.io,swarm-hooks/swarm,jimmycmh/swarm,joaofnfernandes/docker.github.io,ezrasilvera/SwarmACLs,thaJeztah/docker.github.io,BSWANG/denverdino.github.io,srikalyan/swarm,denverdino/swarm,jzwlqx/denverdino.github.io,londoncalling/docker.github.io,bpradipt/swarm,mgoelzer/swarm,auzias/swarm,u2mejc/swarm,anweiss/docker.github.io,johnstep/docker.github.io,docker-zh/docker.github.io,shahankhatch/swarm,alexisbellido/docker.github.io,docker/docker.github.io,mgoelzer/swarm,aduermael/docker.github.io,everett-toews/swarm,barais/swarm,akerbis/armhf-swarm,sanscontext/docker.github.io,sanscontext/docker.github.io,alexisbellido/docker.github.io,ehazlett/swarm,alexisbellido/docker.github.io,CodeNow/swarm,bdwill/docker.github.io,docker-zh/docker.github.io,EderRoger/swarm,thaJeztah/docker.github.io,qianzhangxa/swarm,alexisbellido/docker.github.io,LuisBosquez/docker.github.io,denverdino/denverdino.github.io,FollowMyDev/swarm,BSWANG/denverdino.github.io,menglingwei/denverdino.github.io,JimGalasyn/docker.github.io,JimGalasyn/docker.github.io,gonkulator/swarm,allencloud/swarm,bdwill/docker.github.io,xFragger/swarm,polyverse-security/swarm,riuvshin/swarm,FreedomWangLi/swarm,troy0820/docker.github.io,cpuguy83/swarm,danix800/docker.github.io,LukasBacigal/swarm,denverdino/docker.github.io,fugr/swarm,morpheyesh/swarm,bsmr-docker/swarm,pdevine/swarm,bsmr-docker/swarm,resouer/swarm,menglingwei/denverdino.github.io,vlajos/swarm,adouang/swarm,sanscontext/docker.github.io,jdamick/swarm,srikalyan/swarm,rancher/swarm,joeuo/docker.github.io,menglingwei/denverdino.github.io,rchicoli/swarm,ezrasilvera/swarm,dims/swarm,kunalkushwaha/swarm,iaintshine/swarm,echupriyanov/swarm,aduermael/docker.github.io,riuvshin/swarm,ehazlett/swarm,phiroict/docker,londoncalling/docker.github.io,zkcrescent/swarm,johnstep/docker.github.io,denverdino/denverdino.github.io,phiroict/docker,yp-engineering/swarm,ch3lo/swarm,errordeveloper/swarm,gdevillele/docker.github.io,shahankhatch/swarm,schmunk42/swarm,danix800/docker.github.io,everett-toews/swarm,mrjana/swarm,denverdino/docker.github.io,tangkun75/swarm,rillig/docker.github.io,shubheksha/docker.github.io,krystism/swarm,pssahi/swarm,CiaranCostello/swarm,cpuguy83/swarm,denverdino/docker.github.io,parapsyche/swarm,megamsys/swarm,anweiss/docker.github.io,tranceitionalMynd/swarm,vlajos/swarm,zkcrescent/swarm,rchicoli/swarm,FollowMyDev/swarm,jzwlqx/denverdino.github.io,gdevillele/docker.github.io,kyhavlov/swarm,jeffjen/swarm,qianzhangxa/swarm,megamsys/swarm,shubheksha/docker.github.io,ricca742/swarm,ezrasilvera/SwarmACLs,pdevine/swarm,denverdino/denverdino.github.io,JimGalasyn/docker.github.io,allencloud/swarm,ch3lo/swarm,phiroict/docker,unodba/swarm,echupriyanov/swarm,bdwill/docker.github.io,jimmycmh/swarm,jdamick/swarm,beni55/swarm-1,cgvarela/swarm,dims/swarm,Aorjoa/swarm,denverdino/swarm-1,christophelec/swarm,schmunk42/swarm,denverdino/denverdino.github.io,bpradipt/swarm,doronp/swarm,joeuo/docker.github.io,LuisBosquez/docker.github.io,phiroict/docker,joaofnfernandes/docker.github.io,akerbis/armhf-swarm,joeuo/docker.github.io,troy0820/docker.github.io,therealbill/swarm,resouer/swarm,NunoEdgarGub1/swarm,EderRoger/swarm,joaofnfernandes/docker.github.io,swarm-hooks/swarm,krystism/swarm,unodba/swarm,jzwlqx/denverdino.github.io,docker/docker.github.io,beni55/swarm-1,johnstep/docker.github.io,JimGalasyn/docker.github.io,LukasBacigal/swarm,MHBauer/swarm,gdevillele/docker.github.io,jzwlqx/denverdino.github.io,Spritekin/swarm,linecheng/swarm