Revert "builder/virtualbox: Copy ISO because VirtualBox can't recognize"
Revert "builder/virtualbox: Copy ISO because VirtualBox can't recognize"

This reverts commit 688be43811007d33b9c70dec93b43782a4f71c06; instead
of copying the ISO (which can be huge), we have adjusted the cache path
to include the extension of the source file.

Conflicts:

	builder/virtualbox/step_download_iso.go

BayanGroup/packer,gildas/packer-hyperv,LinusU/packer,Banno/packer,gbarberi/packer,sean-/packer,Silver90/packer,uber/packer,tomwilkie/packer,sean-/packer,dave2/packer,ldejager/packer,icnocop/packer,pvandervelde/packer,legal90/packer,p1-nico/packer,rickard-von-essen/packer,ldejager/packer,mindjiver/packer,Banno/packer,paulvollmer/packer,shaunduncan/packer,pieter-lazzaro/packer,higebu/packer,manicai/packer,rnaveiras/packer,taliesins/packer,higebu/packer,visioncritical/packer,DualSpark/packer,noplay/packer,taliesins/packer,mitchellh/packer,bradparks/packer__create_vm_for_aws_docker_vagrant_etc,dayglojesus/packer,tas50/packer,evertrue/packer,higebu/packer,visioncritical/packer,Akasurde/packer,monsterzz/packer,esemplare/packer,ldejager/packer,marklap/packer,KohlsTechnology/packer,rnaveiras/packer,gildas/packer-hyperv,mefellows/packer,jonathankarsh/packer,ricardclau/packer,napramirez/packer,markpeek/packer,jae2/packer,bryson/packer,styro/packer,beni55/packer,mohae/packer,justincampbell/packer,stagrlee/packer,yoctocloud/packer,sobrinho/packer,ChrisLundquist/packer,jonathankarsh/packer,pecigonzalo/packer,dantran/packer,youhong316/packer,DualSpark/packer,youhong316/packer,KFishner/packer,hasJackb/packer,pvandervelde/packer,smaato/packer,rickard-von-essen/packer,zakuro9715/packer,bensojona/packer,LinusU/packer,mohae/packer,noplay/packer,tb3088/packer,aneeshusa/packer,burnzy/packer,aneeshusa/packer,danschaffer/packer,jamesleech/packer,rodm/packer,hashicorp/packer,jonathankarsh/packer,markpeek/packer,qur/packer,KohlsTechnology/packer,dave2/packer,dieu/packer,monsterzz/packer,fnoeding/packer,ephemeralsnow/packer,dave2/packer,arizvisa/packer,rnaveiras/packer,orivej/packer,routelastresort/packer,visioncritical/packer,ChrisLundquist/packer,mvanholsteijn/packer,kpettijohn/packer,mkuzmin/packer,trumant/packer,mayflower/packer,pieter-lazzaro/packer,boumenot/packer,Cbeck527/packer,samdunne/packer,tsmolka/packer,masbog/packer,pvandervelde/packer,mayflower/packer,qur/packer,KohlsTechnology/packer,btd/packer,marklap/packer,vtolstov/packer,beni55/packer,mitchellh/packer,evertrue/packer,sobrinho/packer,bensojona/packer,DualSpark/packer,styro/packer,kgrvamsi/packer,jszwedko/packer,threatstream/packer,rickard-von-essen/packer,jsternberg/packer,monkeylittleinc/packer,sneal/packer,arizvisa/packer,rickard-von-essen/packer,dayglojesus/packer,markpeek/packer,sgirones/packer,hashicorp/packer,BayanGroup/packer,aneeshusa/packer,threatstream/packer,boumenot/packer,bryson/packer,yonglehou/packer,higebu/packer,blairham/packer,dragon788/packer,ttaylor249/packer,grange74/packer,mefellows/packer,dave2/packer,grubernaut/packer,mkuzmin/packer,BayanGroup/packer,mafrosis/packer,danschaffer/packer,jen20/packer,pvandervelde/packer,cyberhouse/packer,jmptrader/packer,mansunkuo/packer,hazelesque/packer,arizvisa/packer,mindjiver/packer,ricardclau/packer,justincampbell/packer,vtolstov/packer,fnoeding/packer,paulmey/packer,legal90/packer,btd/packer,israelshirk/packer,jae2/packer,timsutton/packer,yoctocloud/packer,paulvollmer/packer,grubernaut/packer,hasJackb/packer,tracyde/packer,grange74/packer,shaunduncan/packer,pieter-lazzaro/packer,masbog/packer,mgk/packer,AlphaStaxLLC/packer,jsoriano/packer,mwhooker/packer,tsmolka/packer,rk295/packer,mwhooker/packer,mindjiver/packer,tsmolka/packer,pvanbuijtene/packer,tomwilkie/packer,vtolstov/packer,tas50/packer,jszwedko/packer,pecigonzalo/packer,napramirez/packer,threatstream/packer,burnzy/packer,AlphaStaxLLC/packer,c22/packer,feateds/packer,jszwedko/packer,pearkes/packer,evertrue/packer,tomwilkie/packer,taliesins/packer,legal90/packer,gbarberi/packer,gildas/packer-hyperv,sequenceiq/packer,sobrinho/packer,rodm/packer,rnaveiras/packer,marklap/packer,pvanbuijtene/packer,sean-/packer,markpeek/packer,smaato/packer,dragon788/packer,Akasurde/packer,icnocop/packer,bensojona/packer,oliviertremblay/packer,smaato/packer,jszwedko/packer,pvanbuijtene/packer,mvanholsteijn/packer,ttaylor249/packer,jean/packer,mayflower/packer,taliesins/packer,mohae/packer,henrysher/packer,boumenot/packer,paulmey/packer,ChrisLundquist/packer,beni55/packer,justincampbell/packer,jgkim/packer,jasonchaffee/packer,quantang/packer,bryson/packer,jmptrader/packer,zhuzhih2017/packer,zakuro9715/packer,jen20/packer,monkeylittleinc/packer,trumant/packer,dragon788/packer,Cbeck527/packer,icnocop/packer,marc-ta/packer,ober/packer,youhong316/packer,atlassian/packer,Akasurde/packer,Sheile/packer,arizvisa/packer,zakuro9715/packer,sansb/packer,p1-nico/packer,pecigonzalo/packer,israelshirk/packer,hasJackb/packer,leroux/packer,c22/packer,tomwilkie/packer,danschaffer/packer,atlassian/packer,mgk/packer,atlassian/packer,mansunkuo/packer,ChrisLundquist/packer,bryson/packer,mvanholsteijn/packer,hasJackb/packer,pecigonzalo/packer,bradparks/packer__create_vm_for_aws_docker_vagrant_etc,mansunkuo/packer,life360/packer,sneal/packer,feateds/packer,LinusU/packer,jimmythedog/packer,styro/packer,jamesleech/packer,ricardclau/packer,sean-/packer,styro/packer,icnocop/packer,ttaylor249/packer,zhuzhih2017/packer,LinusU/packer,fnoeding/packer,pvanbuijtene/packer,avldya/packer,marc-ta/packer,Cbeck527/packer,ricardclau/packer,timsutton/packer,dave2/packer,sansb/packer,bensojona/packer,trumant/packer,pvanbuijtene/packer,sobrinho/packer,sequenceiq/packer,tsmolka/packer,sean-/packer,samdunne/packer,taliesins/packer,Banno/packer,dayglojesus/packer,p1-nico/packer,paulmey/packer,gbarberi/packer,DualSpark/packer,dev-head/packer,rrva/packer,henrysher/packer,grange74/packer,mayflower/packer,kgrvamsi/packer,AlphaStaxLLC/packer,dantran/packer,bhcleek/packer,lantrix/packer,life360/packer,rk295/packer,cyberhouse/packer,jsoriano/packer,ephemeralsnow/packer,danschaffer/packer,shaunduncan/packer,mkuzmin/packer,visioncritical/packer,KohlsTechnology/packer,dev-head/packer,sgirones/packer,life360/packer,rnaveiras/packer,jimmythedog/packer,sansb/packer,marc-ta/packer,jamesbishopp/packer,noplay/packer,Cbeck527/packer,p1-nico/packer,jae2/packer,beni55/packer,ephemeralsnow/packer,blairham/packer,danschaffer/packer,ttaylor249/packer,jsternberg/packer,mgk/packer,zeliff/packer,oliviertremblay/packer,manicai/packer,mitchellh/packer,tracyde/packer,jarl-dk/packer,timsutton/packer,smaato/packer,qur/packer,youhong316/packer,p1-nico/packer,legal90/packer,higebu/packer,henrysher/packer,qur/packer,cyberhouse/packer,lantrix/packer,arizvisa/packer,Xiol/packer,quantang/packer,atlassian/packer,tb3088/packer,pieter-lazzaro/packer,AlphaStaxLLC/packer,yoctocloud/packer,monsterzz/packer,dantran/packer,rrva/packer,KohlsTechnology/packer,rodm/packer,umang1912/packer,orivej/packer,ober/packer,life360/packer,routelastresort/packer,arizvisa/packer,sequenceiq/packer,jonathankarsh/packer,bhcleek/packer,mkuzmin/packer,mitchellh/packer,rickard-von-essen/packer,jean/packer,kpettijohn/packer,pearkes/packer,manicai/packer,grubernaut/packer,jen20/packer,mafrosis/packer,sgirones/packer,napramirez/packer,jmptrader/packer,mwhooker/packer,Silver90/packer,jamesbishopp/packer,uber/packer,eranchetz/packer,pieter-lazzaro/packer,tb3088/packer,esemplare/packer,burnzy/packer,atlassian/packer,yoctocloud/packer,hazelesque/packer,jmptrader/packer,jasonchaffee/packer,mwhooker/packer,monkeylittleinc/packer,zhuzhih2017/packer,zeliff/packer,eranchetz/packer,kgrvamsi/packer,tas50/packer,ChrisLundquist/packer,rrva/packer,jgkim/packer,rodm/packer,eranchetz/packer,oliviertremblay/packer,sneal/packer,Silver90/packer,israelshirk/packer,legal90/packer,vtolstov/packer,youhong316/packer,threatstream/packer,leroux/packer,dev-head/packer,timsutton/packer,bhcleek/packer,tsmolka/packer,rk295/packer,Akasurde/packer,dayglojesus/packer,Xiol/packer,vtolstov/packer,israelshirk/packer,pieter-lazzaro/packer,mvanholsteijn/packer,jen20/packer,mindjiver/packer,marc-ta/packer,routelastresort/packer,tb3088/packer,Xiol/packer,paulvollmer/packer,tracyde/packer,tb3088/packer,sneal/packer,mefellows/packer,jarl-dk/packer,ChrisLundquist/packer,mwhooker/packer,ldejager/packer,samdunne/packer,jimmythedog/packer,Xiol/packer,quantang/packer,stagrlee/packer,justincampbell/packer,timsutton/packer,dantran/packer,napramirez/packer,tsmolka/packer,Silver90/packer,yonglehou/packer,jen20/packer,c22/packer,jsoriano/packer,mafrosis/packer,dieu/packer,jasonchaffee/packer,manicai/packer,tracyde/packer,mohae/packer,blairham/packer,c22/packer,jae2/packer,youhong316/packer,routelastresort/packer,grubernaut/packer,avldya/packer,Akasurde/packer,jasonchaffee/packer,quantang/packer,boumenot/packer,esemplare/packer,c22/packer,dayglojesus/packer,dantran/packer,mafrosis/packer,jean/packer,p1-nico/packer,stagrlee/packer,zakuro9715/packer,sgirones/packer,tb3088/packer,ephemeralsnow/packer,tas50/packer,tas50/packer,avldya/packer,ober/packer,smaato/packer,pvandervelde/packer,burnzy/packer,dragon788/packer,mayflower/packer,routelastresort/packer,jean/packer,yonglehou/packer,blairham/packer,mafrosis/packer,smaato/packer,grubernaut/packer,bradparks/packer__create_vm_for_aws_docker_vagrant_etc,sneal/packer,yoctocloud/packer,paulmey/packer,jimmythedog/packer,btd/packer,Sheile/packer,grubernaut/packer,ttaylor249/packer,esemplare/packer,uber/packer,rrva/packer,ober/packer,jsoriano/packer,lantrix/packer,jasonchaffee/packer,feateds/packer,jsternberg/packer,dieu/packer,jarl-dk/packer,pearkes/packer,bradparks/packer__create_vm_for_aws_docker_vagrant_etc,zeliff/packer,mefellows/packer,jgkim/packer,grange74/packer,zhuzhih2017/packer,jamesbishopp/packer,KFishner/packer,markpeek/packer,paulvollmer/packer,bhcleek/packer,taliesins/packer,stagrlee/packer,jgkim/packer,umang1912/packer,bryson/packer,feateds/packer,rk295/packer,fnoeding/packer,kpettijohn/packer,Sheile/packer,esemplare/packer,orivej/packer,orivej/packer,pvandervelde/packer,samdunne/packer,btd/packer,ephemeralsnow/packer,quantang/packer,monkeylittleinc/packer,kgrvamsi/packer,mgk/packer,shaunduncan/packer,zhuzhih2017/packer,tas50/packer,KohlsTechnology/packer,dieu/packer,paulmey/packer,mkuzmin/packer,ober/packer,mohae/packer,Sheile/packer,hashicorp/packer,pearkes/packer,trumant/packer,KFishner/packer,sansb/packer,umang1912/packer,mansunkuo/packer,jen20/packer,c22/packer,marklap/packer,kpettijohn/packer,gildas/packer-hyperv,jamesleech/packer,uber/packer,mansunkuo/packer,bhcleek/packer,paulmey/packer,eranchetz/packer,monkeylittleinc/packer,sean-/packer,jamesbishopp/packer,BayanGroup/packer,cyberhouse/packer,sequenceiq/packer,hashicorp/packer,atlassian/packer,zhuzhih2017/packer,masbog/packer,life360/packer,evertrue/packer,oliviertremblay/packer,grange74/packer,jamesleech/packer,jimmythedog/packer,KFishner/packer,leroux/packer,jarl-dk/packer,markpeek/packer,threatstream/packer,masbog/packer,mitchellh/packer,boumenot/packer,icnocop/packer,ricardclau/packer,gbarberi/packer,hazelesque/packer,jsternberg/packer,leroux/packer,zeliff/packer,dev-head/packer,dave2/packer,yonglehou/packer,avldya/packer,ricardclau/packer,bryson/packer,mkuzmin/packer,umang1912/packer,samdunne/packer,aneeshusa/packer,rnaveiras/packer,Cbeck527/packer,noplay/packer,hazelesque/packer,monsterzz/packer,henrysher/packer,lantrix/packer,timsutton/packer