Fix bundler env after recent change with Gemfiles (#7313)
Fix bundler env after recent change with Gemfiles (#7313)

Before that, the following error was shown

```
[11:52:27]: Exit status of command 'bundle install' was 1 instead of 0.
/Users/fkrause/Developer/fastlane/spaceship/Gemfile:2:in `read':  (Bundler::Dsl::DSLError)
[!] There was an error parsing `Gemfile`: No such file or directory @ rb_sysopen - Gemfile. Bundler cannot continue.

 #  from /Users/fkrause/Developer/fastlane/spaceship/Gemfile:2
 #  -------------------------------------------
 #  Dir.chdir("..") do
 >    eval File.read("Gemfile")
 #  end
 #  -------------------------------------------
	from /Users/fkrause/Developer/fastlane/spaceship/Gemfile:2:in `block in eval_gemfile'
	from /Users/fkrause/Developer/fastlane/spaceship/Gemfile:1:in `chdir'
	from /Users/fkrause/Developer/fastlane/spaceship/Gemfile:1:in `eval_gemfile'
	from /Users/fkrause/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/bundler-1.13.3/lib/bundler/dsl.rb:41:in `instance_eval'
	from /Users/fkrause/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/bundler-1.13.3/lib/bundler/dsl.rb:41:in `eval_gemfile'
	from /Users/fkrause/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/bundler-1.13.3/lib/bundler/dsl.rb:11:in `evaluate'
	from /Users/fkrause/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/bundler-1.13.3/lib/bundler/definition.rb:33:in `build'
	from /Users/fkrause/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/bundler-1.13.3/lib/bundler.rb:127:in `definition'
	from /Users/fkrause/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/bundler-1.13.3/lib/bundler.rb:93:in `setup'
	from /Users/fkrause/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/bundler-1.13.3/lib/bundler/setup.rb:20:in `<top (required)>'
	from /Users/fkrause/.rbenv/versions/2.2.1/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /Users/fkrause/.rbenv/versions/2.2.1/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
```

This way we'll ensure the local Gemfile isn't used for our docs
Fanagame/fastlane,milch/fastlane,luongm/fastlane,ashfurrow/fastlane,manuyavuz/fastlane,Econa77/fastlane,olegoid/fastlane,cpunion/fastlane,allewun/fastlane,taquitos/fastlane,keatongreve/fastlane,SiarheiFedartsou/fastlane,sinoru/fastlane,taquitos/fastlane,matthewellis/fastlane,futuretap/fastlane,ashfurrow/fastlane,iCell/fastlane,ashfurrow/fastlane,ExtremeMan/fastlane,ffittschen/fastlane,Fanagame/fastlane,adellibovi/fastlane,jaleksynas/fastlane,manuyavuz/fastlane,dral3x/fastlane,adellibovi/fastlane,fulldecent/fastlane,luongm/fastlane,nafu/fastlane,bassrock/fastlane,Fanagame/fastlane,cpunion/fastlane,sinoru/fastlane,RishabhTayal/fastlane,bolom/fastlane,tmtrademarked/fastlane,RishabhTayal/fastlane,joshdholtz/fastlane,revile/fastlane,matthewellis/fastlane,mathiasAichinger/fastlane,farkasseb/fastlane,sinoru/fastlane,nafu/fastlane,kazuhidet/fastlane,farkasseb/fastlane,hjanuschka/fastlane,tommeier/fastlane,danielbowden/fastlane,mathiasAichinger/fastlane,kazuhidet/fastlane,milch/fastlane,Econa77/fastlane,adamcohenrose/fastlane,cpunion/fastlane,nafu/fastlane,vronin/fastlane,mbogh/fastlane,thasegaw/fastlane,daveanderson/fastlane,ExtremeMan/fastlane,nafu/fastlane,fulldecent/fastlane,revile/fastlane,cpk1/fastlane,kohtenko/fastlane,brbulic/fastlane,mathiasAichinger/fastlane,kazuhidet/fastlane,ExtremeMan/fastlane,thasegaw/fastlane,farkasseb/fastlane,allewun/fastlane,SiarheiFedartsou/fastlane,fabiomassimo/fastlane,thasegaw/fastlane,nafu/fastlane,cpunion/fastlane,rimarsh/fastlane,enozero/fastlane,vronin/fastlane,matthewellis/fastlane,powtac/fastlane,icecrystal23/fastlane,fastlane/fastlane,jaleksynas/fastlane,KrauseFx/fastlane,keatongreve/fastlane,powtac/fastlane,bolom/fastlane,brbulic/fastlane,sinoru/fastlane,mathiasAichinger/fastlane,adellibovi/fastlane,dral3x/fastlane,fastlane/fastlane,lacostej/fastlane,tommeier/fastlane,hjanuschka/fastlane,cpunion/fastlane,adamcohenrose/fastlane,danielbowden/fastlane,mbogh/fastlane,icecrystal23/fastlane,bolom/fastlane,iMokhles/fastlane,SiarheiFedartsou/fastlane,farkasseb/fastlane,revile/fastlane,danielbowden/fastlane,hjanuschka/fastlane,ashfurrow/fastlane,brbulic/fastlane,olegoid/fastlane,mgrebenets/fastlane,NicholasFFox/fastlane,bassrock/fastlane,powtac/fastlane,ffittschen/fastlane,tommeier/fastlane,fulldecent/fastlane,vronin/fastlane,tmtrademarked/fastlane,kazuhidet/fastlane,daveanderson/fastlane,Sajjon/fastlane,powtac/fastlane,SiarheiFedartsou/fastlane,taquitos/fastlane,thasegaw/fastlane,javibm/fastlane,hjanuschka/fastlane,taquitos/fastlane,sinoru/fastlane,hjanuschka/fastlane,nafu/fastlane,NicholasFFox/fastlane,cpunion/fastlane,mathiasAichinger/fastlane,taquitos/fastlane,adellibovi/fastlane,kohtenko/fastlane,jaleksynas/fastlane,lyndsey-ferguson/fastlane,vronin/fastlane,ffittschen/fastlane,Fanagame/fastlane,tommeier/fastlane,iMokhles/fastlane,kazuhidet/fastlane,dral3x/fastlane,SemenovAlexander/fastlane,Sajjon/fastlane,tommeier/fastlane,jaleksynas/fastlane,luongm/fastlane,iCell/fastlane,joshdholtz/fastlane,marcelofabri/fastlane,lyndsey-ferguson/fastlane,mathiasAichinger/fastlane,NicholasFFox/fastlane,mbogh/fastlane,joshdholtz/fastlane,RishabhTayal/fastlane,powtac/fastlane,Sajjon/fastlane,powtac/fastlane,bolom/fastlane,mbogh/fastlane,jaleksynas/fastlane,fabiomassimo/fastlane,lacostej/fastlane,enozero/fastlane,soxjke/fastlane,milch/fastlane,daveanderson/fastlane,Fanagame/fastlane,futuretap/fastlane,olegoid/fastlane,lyndsey-ferguson/fastlane,iMokhles/fastlane,milch/fastlane,mgrebenets/fastlane,marcelofabri/fastlane,adamcohenrose/fastlane,ashfurrow/fastlane,SiarheiFedartsou/fastlane,brbulic/fastlane,manuyavuz/fastlane,fastlane/fastlane,lacostej/fastlane,brbulic/fastlane,fulldecent/fastlane,icecrystal23/fastlane,Econa77/fastlane,farkasseb/fastlane,enozero/fastlane,brbulic/fastlane,ffittschen/fastlane,icecrystal23/fastlane,NicholasFFox/fastlane,allewun/fastlane,adamcohenrose/fastlane,mathiasAichinger/fastlane,rimarsh/fastlane,mbogh/fastlane,revile/fastlane,javibm/fastlane,matthewellis/fastlane,iCell/fastlane,danielbowden/fastlane,Econa77/fastlane,cpunion/fastlane,farkasseb/fastlane,bassrock/fastlane,Econa77/fastlane,SemenovAlexander/fastlane,marcelofabri/fastlane,thasegaw/fastlane,marcelofabri/fastlane,tmtrademarked/fastlane,futuretap/fastlane,iMokhles/fastlane,ffittschen/fastlane,manuyavuz/fastlane,keatongreve/fastlane,ExtremeMan/fastlane,daveanderson/fastlane,enozero/fastlane,ExtremeMan/fastlane,mgrebenets/fastlane,joshdholtz/fastlane,hjanuschka/fastlane,Sajjon/fastlane,bassrock/fastlane,KrauseFx/fastlane,thasegaw/fastlane,fastlane/fastlane,brbulic/fastlane,rimarsh/fastlane,tmtrademarked/fastlane,mgrebenets/fastlane,daveanderson/fastlane,icecrystal23/fastlane,orta/fastlane,ashfurrow/fastlane,jaleksynas/fastlane,Fanagame/fastlane,iCell/fastlane,fastlane/fastlane,cpk1/fastlane,olegoid/fastlane,SemenovAlexander/fastlane,marcelofabri/fastlane,fabiomassimo/fastlane,lyndsey-ferguson/fastlane,taquitos/fastlane,iCell/fastlane,lyndsey-ferguson/fastlane,rimarsh/fastlane,KrauseFx/fastlane,SemenovAlexander/fastlane,revile/fastlane,rimarsh/fastlane,soxjke/fastlane,KrauseFx/fastlane,danielbowden/fastlane,milch/fastlane,bolom/fastlane,sinoru/fastlane,enozero/fastlane,rimarsh/fastlane,ExtremeMan/fastlane,joshdholtz/fastlane,iMokhles/fastlane,rimarsh/fastlane,milch/fastlane,lacostej/fastlane,iCell/fastlane,mbogh/fastlane,marcelofabri/fastlane,kazuhidet/fastlane,thasegaw/fastlane,tmtrademarked/fastlane,fulldecent/fastlane,Econa77/fastlane,marcelofabri/fastlane,luongm/fastlane,dral3x/fastlane,javibm/fastlane,Sajjon/fastlane,cpk1/fastlane,soxjke/fastlane,danielbowden/fastlane,javibm/fastlane,orta/fastlane,allewun/fastlane,RishabhTayal/fastlane,icecrystal23/fastlane,soxjke/fastlane,powtac/fastlane,adellibovi/fastlane,lacostej/fastlane,iMokhles/fastlane,SiarheiFedartsou/fastlane,danielbowden/fastlane,Sajjon/fastlane,javibm/fastlane,jaleksynas/fastlane,daveanderson/fastlane,cpk1/fastlane,allewun/fastlane,mgrebenets/fastlane,lyndsey-ferguson/fastlane,dral3x/fastlane,soxjke/fastlane,dral3x/fastlane,taquitos/fastlane,adamcohenrose/fastlane,adellibovi/fastlane,lacostej/fastlane,milch/fastlane,tommeier/fastlane,ExtremeMan/fastlane,revile/fastlane,futuretap/fastlane,cpk1/fastlane,luongm/fastlane,soxjke/fastlane,iMokhles/fastlane,manuyavuz/fastlane,bassrock/fastlane,fulldecent/fastlane,adamcohenrose/fastlane,keatongreve/fastlane,keatongreve/fastlane,olegoid/fastlane,olegoid/fastlane,manuyavuz/fastlane,revile/fastlane,NicholasFFox/fastlane,mgrebenets/fastlane,futuretap/fastlane,KrauseFx/fastlane,luongm/fastlane,NicholasFFox/fastlane,bolom/fastlane,farkasseb/fastlane,Sajjon/fastlane,SemenovAlexander/fastlane,fabiomassimo/fastlane,sinoru/fastlane,matthewellis/fastlane,cpk1/fastlane,dral3x/fastlane,tmtrademarked/fastlane,RishabhTayal/fastlane,futuretap/fastlane,NicholasFFox/fastlane,allewun/fastlane,daveanderson/fastlane,fulldecent/fastlane,mgrebenets/fastlane,kazuhidet/fastlane,fastlane/fastlane,bassrock/fastlane,futuretap/fastlane,KrauseFx/fastlane,ashfurrow/fastlane,mbogh/fastlane,fabiomassimo/fastlane,bolom/fastlane,vronin/fastlane,KrauseFx/fastlane,javibm/fastlane,adamcohenrose/fastlane,joshdholtz/fastlane,enozero/fastlane,Fanagame/fastlane,manuyavuz/fastlane,enozero/fastlane,tommeier/fastlane,javibm/fastlane,fabiomassimo/fastlane,vronin/fastlane,fabiomassimo/fastlane,SiarheiFedartsou/fastlane,RishabhTayal/fastlane,SemenovAlexander/fastlane,keatongreve/fastlane,ffittschen/fastlane,matthewellis/fastlane,cpk1/fastlane,RishabhTayal/fastlane,tmtrademarked/fastlane,adellibovi/fastlane,luongm/fastlane,hjanuschka/fastlane,keatongreve/fastlane,Econa77/fastlane,joshdholtz/fastlane,olegoid/fastlane,ffittschen/fastlane,soxjke/fastlane,nafu/fastlane,SemenovAlexander/fastlane,allewun/fastlane,iCell/fastlane,matthewellis/fastlane,lyndsey-ferguson/fastlane,vronin/fastlane