Simplify code that handles non existing manifests
Simplify code that handles non existing manifests

Signed-off-by: Sylvain Baubeau <b0a7dc08a3f38d713e107103b0a85b0badc14b84@redhat.com>

JimGalasyn/docker.github.io,aprajshekhar/distribution,cyli/distribution,vdemeester/distribution,iskradelta/distribution,bdwill/docker.github.io,thaJeztah/docker.github.io,jmitchell/distribution,codefresh-io/cf-distribution,sebrandon1/distribution,manoj535/distribution,phiroict/docker,beni55/distribution,jwhonce/distribution,sadlil/distribution,aduermael/docker.github.io,anweiss/docker.github.io,BrianBland/distribution,LouisKottmann/distribution,BSWANG/denverdino.github.io,jzwlqx/denverdino.github.io,denverdino/docker.github.io,dv/distribution,denverdino/distribution-stevvooe,troy0820/docker.github.io,thaJeztah/docker.github.io,iskradelta/distribution,dalanlan/distribution,deis/distribution,phiroict/docker,docker/distribution,codefresh-io/cf-distribution,jzwlqx/distribution,13W/distribution,BradleyA/distribution,tdooner/distribution,championv/distribution,calavera/distribution,amitshukla/distribution,BrickXu/distribution,docker-zh/docker.github.io,jzwlqx/denverdino.github.io,joeuo/docker.github.io,denverdino/denverdino.github.io,BSWANG/denverdino.github.io,kmala/distribution,docker-zh/docker.github.io,BrickXu/distribution,lcarstensen/distribution,jordimassaguerpla/distribution,hpcloud/distribution,menglingwei/denverdino.github.io,denverdino/denverdino.github.io,zhaytee/distribution,anweiss/docker.github.io,danix800/docker.github.io,LuisBosquez/docker.github.io,jramseye/distribution,JimGalasyn/docker.github.io,denverdino/distribution,jackpgriffin/distribution,ibuildthecloud/distribution,endophage/distribution,docker/distribution,jramseye/distribution,harche/distribution,ChenLingPeng/distribution,jonboulle/distribution,mattmoor/distribution,shin-/docker.github.io,wangmingshuai/distribution,jhicks-camgian/distribution,arvindkandhare/distribution,lorieri/distribution,13W/distribution,johnstep/docker.github.io,yuwaMSFT2/distribution,shubheksha/docker.github.io,jrjang/distribution,docker/docker.github.io,atyenoria/distribution,liubin/distribution,LuisBosquez/docker.github.io,joaofnfernandes/docker.github.io,aprajshekhar/distribution,RaviTezu/distribution,avinson/distribution,huamai-io/distribution,xiekeyang/distribution,rochacon/distribution,dobril-stanga/distribution,danix800/docker.github.io,RaviTezu/distribution,championv/distribution,lcarstensen/distribution,dmcgowan/distribution,curtiszimmerman/distribution,nateww/distribution,arneluehrs/distribution,joeuo/docker.github.io,higebu/distribution,linearregression/distribution,aaronlehmann/distribution,armbuilds/distribution,menglingwei/denverdino.github.io,RyanDeng/distribution,bsmr-docker/distribution,moxiegirl/distribution,shin-/docker.github.io,imranraja85/distribution,shubheksha/docker.github.io,JimGalasyn/docker.github.io,danix800/docker.github.io,docker/docker.github.io,docker/docker.github.io,alexisbellido/docker.github.io,jwhonce/distribution,anweiss/docker.github.io,thaJeztah/docker.github.io,gdevillele/docker.github.io,alexisbellido/docker.github.io,linearregression/distribution,londoncalling/docker.github.io,humble00/distribution,aybabtme/distribution,zerosign/distribution,johnstep/docker.github.io,armbuilds/distribution,alexisbellido/docker.github.io,alexisbellido/docker.github.io,tt/distribution,anweiss/docker.github.io,stevvooe/distribution,amitshukla/distribution,convox/distribution,imranraja85/distribution,rodacom/docker-hub,tian-xiaobo/distribution,shin-/docker.github.io,joeuo/docker.github.io,mikebrow/distribution,gavioto/distribution,runcom/distribution,denverdino/docker.github.io,shyr/distribution,adambrett-forks/distribution,bigsurge/distribution,BSWANG/denverdino.github.io,lorieri/distribution,baloo/distribution,denverdino/docker.github.io,denverdino/denverdino.github.io,jordimassaguerpla/distribution,pdevine/distribution,troy0820/docker.github.io,denverdino/distribution-stevvooe,docker-zh/docker.github.io,hopkings2008/distribution,jlhawn/distribution,nateww/distribution,mikebrow/distribution,londoncalling/docker.github.io,sallyom/distribution,konstruktoid/distribution,denverdino/denverdino.github.io,thaJeztah/docker.github.io,spacexnice/distribution,rillig/docker.github.io,genedock/distribution,djenriquez/distribution,vdemeester/distribution,sergeyfd/distribution,rodacom/docker-hub,BSWANG/denverdino.github.io,tschoots/distribution,huamai-io/distribution,arvindkandhare/distribution,adambrett-forks/distribution,sanscontext/docker.github.io,djenriquez/distribution,bdwill/docker.github.io,schu/distribution,docker/docker.github.io,jmitchell/distribution,phiroict/docker,menglingwei/denverdino.github.io,spacexnice/distribution,arneluehrs/distribution,JimGalasyn/docker.github.io,Seb-Solon/distribution,ibuildthecloud/distribution,sanscontext/docker.github.io,tt/distribution,dave-tucker/distribution,johnstep/docker.github.io,wangmingshuai/distribution,atyenoria/distribution,convox/distribution,estesp/distribution,zerosign/distribution,bsmr-docker/distribution,LuisBosquez/docker.github.io,dv/distribution,rbarlow/distribution,aduermael/docker.github.io,sthapaun/distribution,thaJeztah/docker.github.io,andrewnguyen/distribution,mattrgreen/distribution,cezarsa/distribution,endophage/distribution,AoJ/distribution,sthapaun/distribution,sallyom/distribution,miminar/distribution,beni55/distribution,avinson/distribution,thelinuxkid/distribution,nevermosby/distribution,shubheksha/docker.github.io,shin-/docker.github.io,jonboulle/distribution,troy0820/docker.github.io,harche/distribution,rhoml/distribution,Tiesheng/distribution,aaronlehmann/distribution,moxiegirl/distribution,RichardScothern/distribution,thaJeztah/distribution,bdwill/docker.github.io,denverdino/docker.github.io,LuisBosquez/docker.github.io,alexisbellido/docker.github.io,dalanlan/distribution,harrisonfeng/distribution,RichardScothern/distribution,thelinuxkid/distribution,rillig/docker.github.io,rochacon/distribution,hpcloud/distribution,duglin/distribution,Seb-Solon/distribution,bdwill/docker.github.io,nwt/distribution,sebrandon1/distribution,bigsurge/distribution,mbentley/distribution,londoncalling/docker.github.io,aybabtme/distribution,JimGalasyn/docker.github.io,docker-zh/docker.github.io,johnstep/docker.github.io,jhicks-camgian/distribution,deis/distribution,nevermosby/distribution,shubheksha/docker.github.io,yeghishe/distribution,gavioto/distribution,rillig/docker.github.io,curtiszimmerman/distribution,yeghishe/distribution,jzwlqx/denverdino.github.io,andrewnguyen/distribution,joaofnfernandes/docker.github.io,lindenlab/distribution,cyli/distribution,aduermael/docker.github.io,Tiesheng/distribution,joaofnfernandes/docker.github.io,mattmoor/distribution,miminar/distribution,dave-tucker/distribution,sergeyfd/distribution,konnase/distribution,humble00/distribution,thaJeztah/distribution,LuisBosquez/docker.github.io,xiekeyang/distribution,higebu/distribution,denverdino/denverdino.github.io,mattrgreen/distribution,sadlil/distribution,sanscontext/docker.github.io,denverdino/docker.github.io,sanscontext/docker.github.io,ContainerSolutions/distribution,BrianBland/distribution,AoJ/distribution,jzwlqx/denverdino.github.io,paulczar/distribution,shyr/distribution,joaofnfernandes/docker.github.io,phiroict/docker,yuwaMSFT2/distribution,jzwlqx/denverdino.github.io,tdooner/distribution,BradleyA/distribution,n1tr0g/distribution,rhoml/distribution,noxiouz/distribution,RyanDeng/distribution,bxy09/distribution,denverdino/distribution,docker/docker.github.io,rbarlow/distribution,joeuo/docker.github.io,johnstep/docker.github.io,londoncalling/docker.github.io,LouisKottmann/distribution,gdevillele/docker.github.io,dmcgowan/distribution,harrisonfeng/distribution,sanscontext/docker.github.io,CodeJuan/distribution,ContainerSolutions/distribution,genedock/distribution,jlhawn/distribution,noxiouz/distribution,n1tr0g/distribution,runcom/distribution,joeuo/docker.github.io,danix800/docker.github.io,joaofnfernandes/docker.github.io,menglingwei/denverdino.github.io,rillig/docker.github.io,shin-/docker.github.io,anweiss/docker.github.io,pdevine/distribution,konnase/distribution,bxy09/distribution,baloo/distribution,lindenlab/distribution,troy0820/docker.github.io,nwt/distribution,jzwlqx/distribution,docker-zh/docker.github.io,paulczar/distribution,dobril-stanga/distribution,jackpgriffin/distribution,Gobliip/distribution,estesp/distribution,hopkings2008/distribution,zhaytee/distribution,shubheksha/docker.github.io,konstruktoid/distribution,manoj535/distribution,londoncalling/docker.github.io,aduermael/docker.github.io,bpradipt/distribution,stevvooe/distribution,ChenLingPeng/distribution,mbentley/distribution,gdevillele/docker.github.io,calavera/distribution,CodeJuan/distribution,cezarsa/distribution,tian-xiaobo/distribution,jrjang/distribution,tschoots/distribution,gdevillele/docker.github.io,menglingwei/denverdino.github.io,phiroict/docker,duglin/distribution,bdwill/docker.github.io,BSWANG/denverdino.github.io,bpradipt/distribution,kmala/distribution,schu/distribution,gdevillele/docker.github.io,Gobliip/distribution,liubin/distribution