Improved error message when a gem is not installed
Improved error message when a gem is not installed

Fixes https://github.com/fastlane/fastlane/issues/1339

KrauseFx/fastlane,sylvek/fastlane,thelvis4/fastlane,marcelofabri/fastlane,iMokhles/fastlane,futuretap/fastlane,mandrizzle/fastlane,bolom/fastlane,jfresen/fastlane,iCell/fastlane,soxjke/fastlane,enozero/fastlane,powtac/fastlane,tpalmer/fastlane,milch/fastlane,dral3x/fastlane,Liquidsoul/fastlane,lyndsey-ferguson/fastlane,lacostej/fastlane,danielbowden/fastlane,iCell/fastlane,tpalmer/fastlane,mbogh/fastlane,iCell/fastlane,taquitos/fastlane,futuretap/fastlane,daveanderson/fastlane,futuretap/fastlane,fastlane/fastlane,phatblat/fastlane,joshrlesch/fastlane,lyndsey-ferguson/fastlane,SiarheiFedartsou/fastlane,SandyChapman/fastlane,farkasseb/fastlane,olegoid/fastlane,tommeier/fastlane,fabiomassimo/fastlane,jeeftor/fastlane,luongm/fastlane,SandyChapman/fastlane,milch/fastlane,thasegaw/fastlane,SandyChapman/fastlane,sinoru/fastlane,nafu/fastlane,dral3x/fastlane,bassrock/fastlane,daveanderson/fastlane,bgannin/fastlane,st3fan/fastlane,sinoru/fastlane,sinoru/fastlane,jzallas/fastlane,taquitos/fastlane,NicholasFFox/fastlane,st3fan/fastlane,Liquidsoul/fastlane,jaleksynas/fastlane,neonichu/fastlane,luongm/fastlane,daveanderson/fastlane,manuyavuz/fastlane,phatblat/fastlane,tcurdt/fastlane,powtac/fastlane,Fanagame/fastlane,sinoru/fastlane,SemenovAlexander/fastlane,phatblat/fastlane,iMokhles/fastlane,cbowns/fastlane,revile/fastlane,fulldecent/fastlane,lmirosevic/fastlane,ExtremeMan/fastlane,enozero/fastlane,Acorld/fastlane,icecrystal23/fastlane,ffittschen/fastlane,smallmiro/fastlane,manuyavuz/fastlane,Sajjon/fastlane,jfresen/fastlane,nafu/fastlane,revile/fastlane,milch/fastlane,kohtenko/fastlane,manuyavuz/fastlane,mathiasAichinger/fastlane,st3fan/fastlane,fastlane/fastlane,enozero/fastlane,farkasseb/fastlane,SiarheiFedartsou/fastlane,marcelofabri/fastlane,fcy/fastlane,st3fan/fastlane,sylvek/fastlane,RishabhTayal/fastlane,nafu/fastlane,kazuhidet/fastlane,fabiomassimo/fastlane,mathiasAichinger/fastlane,lacostej/fastlane,carlosefonseca/fastlane,mbogh/fastlane,joshrlesch/fastlane,oronbz/fastlane,kohtenko/fastlane,jfresen/fastlane,fastlane/fastlane,bolom/fastlane,bassrock/fastlane,fabiomassimo/fastlane,jeeftor/fastlane,adamcohenrose/fastlane,enozero/fastlane,cbowns/fastlane,ExtremeMan/fastlane,bolom/fastlane,sschlein/fastlane,sinoru/fastlane,tommeier/fastlane,fulldecent/fastlane,fcy/fastlane,fulldecent/fastlane,sschlein/fastlane,ashfurrow/fastlane,adellibovi/fastlane,dral3x/fastlane,fcy/fastlane,jaleksynas/fastlane,jorgeazevedo/fastlane,jzallas/fastlane,futuretap/fastlane,tcurdt/fastlane,tmtrademarked/fastlane,kazuhidet/fastlane,cbowns/fastlane,SandyChapman/fastlane,hjanuschka/fastlane,mandrizzle/fastlane,mandrizzle/fastlane,hjanuschka/fastlane,enozero/fastlane,vronin/fastlane,mgrebenets/fastlane,jaleksynas/fastlane,adamcohenrose/fastlane,dowjones/fastlane,sylvek/fastlane,tpalmer/fastlane,sschlein/fastlane,keatongreve/fastlane,ashfurrow/fastlane,danielbowden/fastlane,manuyavuz/fastlane,sinoru/fastlane,busce/fastlane,soxjke/fastlane,busce/fastlane,soxjke/fastlane,ashfurrow/fastlane,bolom/fastlane,dowjones/fastlane,vronin/fastlane,carlosefonseca/fastlane,vronin/fastlane,oronbz/fastlane,adellibovi/fastlane,soxjke/fastlane,futuretap/fastlane,hjanuschka/fastlane,iMokhles/fastlane,jaleksynas/fastlane,marcelofabri/fastlane,lacostej/fastlane,mgrebenets/fastlane,danielbowden/fastlane,RishabhTayal/fastlane,rimarsh/fastlane,thasegaw/fastlane,neonichu/fastlane,allewun/fastlane,keatongreve/fastlane,dowjones/fastlane,jeeftor/fastlane,hjanuschka/fastlane,keatongreve/fastlane,powtac/fastlane,mgrebenets/fastlane,Acorld/fastlane,javibm/fastlane,kndl/fastlane,bgannin/fastlane,matthewellis/fastlane,carlosefonseca/fastlane,mbogh/fastlane,fastlane/fastlane,taquitos/fastlane,tpalmer/fastlane,Econa77/fastlane,mbogh/fastlane,jfresen/fastlane,cpk1/fastlane,ssmiech/fastlane,adamcohenrose/fastlane,ssmiech/fastlane,NicholasFFox/fastlane,vronin/fastlane,fastlane/fastlane,revile/fastlane,SandyChapman/fastlane,joshrlesch/fastlane,milch/fastlane,tmtrademarked/fastlane,olegoid/fastlane,matthewellis/fastlane,mgamer/fastlane,joshdholtz/fastlane,farkasseb/fastlane,busce/fastlane,cpunion/fastlane,iMokhles/fastlane,cpunion/fastlane,keatongreve/fastlane,thelvis4/fastlane,dral3x/fastlane,rimarsh/fastlane,neonichu/fastlane,farkasseb/fastlane,carlosefonseca/fastlane,ashfurrow/fastlane,Econa77/fastlane,fcy/fastlane,oronbz/fastlane,nafu/fastlane,adellibovi/fastlane,sschlein/fastlane,milch/fastlane,mgamer/fastlane,ExtremeMan/fastlane,lmirosevic/fastlane,ssmiech/fastlane,joshdholtz/fastlane,enozero/fastlane,ssmiech/fastlane,milch/fastlane,lmirosevic/fastlane,cpunion/fastlane,lmirosevic/fastlane,lacostej/fastlane,thelvis4/fastlane,mandrizzle/fastlane,olegoid/fastlane,oysta/fastlane,dral3x/fastlane,luongm/fastlane,tcurdt/fastlane,lyndsey-ferguson/fastlane,ssmiech/fastlane,revile/fastlane,SemenovAlexander/fastlane,st3fan/fastlane,marcelofabri/fastlane,cbowns/fastlane,iCell/fastlane,adamcohenrose/fastlane,oysta/fastlane,allewun/fastlane,mgrebenets/fastlane,tcurdt/fastlane,vronin/fastlane,fulldecent/fastlane,tcurdt/fastlane,Acorld/fastlane,Sajjon/fastlane,icecrystal23/fastlane,revile/fastlane,lyndsey-ferguson/fastlane,KrauseFx/fastlane,Econa77/fastlane,jorgeazevedo/fastlane,oysta/fastlane,joshrlesch/fastlane,farkasseb/fastlane,brbulic/fastlane,powtac/fastlane,KrauseFx/fastlane,sylvek/fastlane,ffittschen/fastlane,jorgeazevedo/fastlane,kazuhidet/fastlane,mathiasAichinger/fastlane,thelvis4/fastlane,thelvis4/fastlane,hjanuschka/fastlane,brbulic/fastlane,busce/fastlane,bgerstle/fastlane,mgamer/fastlane,tommeier/fastlane,danielbowden/fastlane,SiarheiFedartsou/fastlane,revile/fastlane,NicholasFFox/fastlane,cbowns/fastlane,SemenovAlexander/fastlane,fastlane/fastlane,jorgeazevedo/fastlane,RishabhTayal/fastlane,tcurdt/fastlane,SemenovAlexander/fastlane,joshrlesch/fastlane,cpk1/fastlane,thelvis4/fastlane,jzallas/fastlane,joshdholtz/fastlane,mandrizzle/fastlane,taquitos/fastlane,soxjke/fastlane,Econa77/fastlane,ffittschen/fastlane,cpk1/fastlane,taquitos/fastlane,revile/fastlane,mgrebenets/fastlane,lacostej/fastlane,thasegaw/fastlane,NicholasFFox/fastlane,brbulic/fastlane,ssmiech/fastlane,phatblat/fastlane,tommeier/fastlane,neonichu/fastlane,NicholasFFox/fastlane,SiarheiFedartsou/fastlane,jeeftor/fastlane,SiarheiFedartsou/fastlane,kndl/fastlane,tmtrademarked/fastlane,matthewellis/fastlane,kndl/fastlane,ffittschen/fastlane,milch/fastlane,fulldecent/fastlane,mbogh/fastlane,ExtremeMan/fastlane,SiarheiFedartsou/fastlane,jaleksynas/fastlane,sschlein/fastlane,cpk1/fastlane,joshdholtz/fastlane,kndl/fastlane,Sajjon/fastlane,javibm/fastlane,sylvek/fastlane,mandrizzle/fastlane,iCell/fastlane,taquitos/fastlane,hjanuschka/fastlane,mgrebenets/fastlane,allewun/fastlane,Liquidsoul/fastlane,tmtrademarked/fastlane,fcy/fastlane,jeeftor/fastlane,SemenovAlexander/fastlane,marcelofabri/fastlane,iCell/fastlane,keatongreve/fastlane,sschlein/fastlane,mathiasAichinger/fastlane,allewun/fastlane,lyndsey-ferguson/fastlane,phatblat/fastlane,powtac/fastlane,bgannin/fastlane,joshdholtz/fastlane,bassrock/fastlane,Acorld/fastlane,bassrock/fastlane,ffittschen/fastlane,rimarsh/fastlane,brbulic/fastlane,neonichu/fastlane,bassrock/fastlane,Fanagame/fastlane,lmirosevic/fastlane,allewun/fastlane,icecrystal23/fastlane,joshdholtz/fastlane,jfresen/fastlane,cpunion/fastlane,busce/fastlane,carlosefonseca/fastlane,lyndsey-ferguson/fastlane,vronin/fastlane,cbowns/fastlane,jorgeazevedo/fastlane,kazuhidet/fastlane,adellibovi/fastlane,dral3x/fastlane,nafu/fastlane,danielbowden/fastlane,nafu/fastlane,icecrystal23/fastlane,daveanderson/fastlane,Acorld/fastlane,javibm/fastlane,ExtremeMan/fastlane,phatblat/fastlane,kazuhidet/fastlane,smallmiro/fastlane,bolom/fastlane,smallmiro/fastlane,ssmiech/fastlane,ffittschen/fastlane,rimarsh/fastlane,orta/fastlane,fabiomassimo/fastlane,mgamer/fastlane,powtac/fastlane,dowjones/fastlane,javibm/fastlane,manuyavuz/fastlane,luongm/fastlane,iMokhles/fastlane,Acorld/fastlane,jaleksynas/fastlane,dowjones/fastlane,lmirosevic/fastlane,oysta/fastlane,sylvek/fastlane,Sajjon/fastlane,bgannin/fastlane,ashfurrow/fastlane,tcurdt/fastlane,thasegaw/fastlane,mgamer/fastlane,rimarsh/fastlane,oronbz/fastlane,oysta/fastlane,keatongreve/fastlane,oysta/fastlane,bolom/fastlane,icecrystal23/fastlane,smallmiro/fastlane,smallmiro/fastlane,danielbowden/fastlane,st3fan/fastlane,rimarsh/fastlane,olegoid/fastlane,matthewellis/fastlane,ExtremeMan/fastlane,SandyChapman/fastlane,cpk1/fastlane,luongm/fastlane,allewun/fastlane,oysta/fastlane,mgamer/fastlane,daveanderson/fastlane,brbulic/fastlane,jorgeazevedo/fastlane,Fanagame/fastlane,cbowns/fastlane,jzallas/fastlane,javibm/fastlane,manuyavuz/fastlane,SemenovAlexander/fastlane,cpunion/fastlane,lyndsey-ferguson/fastlane,mathiasAichinger/fastlane,dowjones/fastlane,bassrock/fastlane,joshrlesch/fastlane,keatongreve/fastlane,kazuhidet/fastlane,javibm/fastlane,lacostej/fastlane,KrauseFx/fastlane,iMokhles/fastlane,cpk1/fastlane,Liquidsoul/fastlane,bgannin/fastlane,fabiomassimo/fastlane,SiarheiFedartsou/fastlane,Fanagame/fastlane,RishabhTayal/fastlane,cpunion/fastlane,olegoid/fastlane,mgrebenets/fastlane,taquitos/fastlane,thasegaw/fastlane,bolom/fastlane,tmtrademarked/fastlane,nafu/fastlane,Fanagame/fastlane,KrauseFx/fastlane,mbogh/fastlane,joshrlesch/fastlane,Sajjon/fastlane,jorgeazevedo/fastlane,olegoid/fastlane,Fanagame/fastlane,Sajjon/fastlane,iMokhles/fastlane,bgerstle/fastlane,adellibovi/fastlane,bgannin/fastlane,thasegaw/fastlane,RishabhTayal/fastlane,Sajjon/fastlane,jzallas/fastlane,farkasseb/fastlane,ExtremeMan/fastlane,cpunion/fastlane,matthewellis/fastlane,kazuhidet/fastlane,mbogh/fastlane,jfresen/fastlane,mathiasAichinger/fastlane,jeeftor/fastlane,sylvek/fastlane,tmtrademarked/fastlane,carlosefonseca/fastlane,hjanuschka/fastlane,tommeier/fastlane,daveanderson/fastlane,RishabhTayal/fastlane,ashfurrow/fastlane,fabiomassimo/fastlane,olegoid/fastlane,Liquidsoul/fastlane,thelvis4/fastlane,ffittschen/fastlane,oronbz/fastlane,thasegaw/fastlane,lmirosevic/fastlane,oronbz/fastlane,kndl/fastlane,danielbowden/fastlane,fulldecent/fastlane,soxjke/fastlane,sschlein/fastlane,luongm/fastlane,mathiasAichinger/fastlane,adamcohenrose/fastlane,KrauseFx/fastlane,jfresen/fastlane,Econa77/fastlane,adellibovi/fastlane,mgamer/fastlane,tmtrademarked/fastlane,Fanagame/fastlane,adamcohenrose/fastlane,Liquidsoul/fastlane,manuyavuz/fastlane,adellibovi/fastlane,jeeftor/fastlane,KrauseFx/fastlane,NicholasFFox/fastlane,vronin/fastlane,luongm/fastlane,matthewellis/fastlane,Econa77/fastlane,dral3x/fastlane,RishabhTayal/fastlane,Econa77/fastlane,neonichu/fastlane,cpk1/fastlane,powtac/fastlane,mandrizzle/fastlane,dowjones/fastlane,allewun/fastlane,oronbz/fastlane,SandyChapman/fastlane,daveanderson/fastlane,SemenovAlexander/fastlane,marcelofabri/fastlane,joshdholtz/fastlane,Acorld/fastlane,brbulic/fastlane,rimarsh/fastlane,farkasseb/fastlane,NicholasFFox/fastlane,fabiomassimo/fastlane,matthewellis/fastlane,phatblat/fastlane,enozero/fastlane,jzallas/fastlane,bgannin/fastlane,busce/fastlane,busce/fastlane,brbulic/fastlane,futuretap/fastlane,kndl/fastlane,smallmiro/fastlane,tpalmer/fastlane,tpalmer/fastlane,icecrystal23/fastlane,ashfurrow/fastlane,st3fan/fastlane,iCell/fastlane,javibm/fastlane,fcy/fastlane,fulldecent/fastlane,tommeier/fastlane,smallmiro/fastlane,jzallas/fastlane,sinoru/fastlane,carlosefonseca/fastlane,neonichu/fastlane,orta/fastlane,marcelofabri/fastlane,soxjke/fastlane,tpalmer/fastlane,adamcohenrose/fastlane,futuretap/fastlane,fcy/fastlane,tommeier/fastlane,Liquidsoul/fastlane,kndl/fastlane,jaleksynas/fastlane