Clarify error message for VAGRANT_HOME [GH-4256]
Clarify error message for VAGRANT_HOME [GH-4256]

philoserf/vagrant,mwrock/vagrant,Chhed13/vagrant,gpkfr/vagrant,taliesins/vagrant,darkn3rd/vagrant,aneeshusa/vagrant,BlakeMesdag/vagrant,lukebakken/vagrant,PatrickLang/vagrant,cgvarela/vagrant,loren-osborn/vagrant,bdwyertech/vagrant,wangfakang/vagrant,clinstid/vagrant,modulexcite/vagrant,philwrenn/vagrant,shtouff/vagrant,kamazee/vagrant,chrisroberts/vagrant,bshurts/vagrant,chrisvire/vagrant,PatOShea/vagrant,senglin/vagrant,kamazee/vagrant,BlakeMesdag/vagrant,apertoso/vagrant,ArloL/vagrant,mwarren/vagrant,krig/vagrant,channui/vagrant,TheBigBear/vagrant,BlakeMesdag/vagrant,benh57/vagrant,patrys/vagrant,senglin/vagrant,marxarelli/vagrant,jfchevrette/vagrant,invernizzi-at-google/vagrant,kamigerami/vagrant,petems/vagrant,carlosefr/vagrant,tknerr/vagrant,vamegh/vagrant,fnewberg/vagrant,TheBigBear/vagrant,PatrickLang/vagrant,tomfanning/vagrant,aaam/vagrant,teotihuacanada/vagrant,shtouff/vagrant,darkn3rd/vagrant,miguel250/vagrant,tschortsch/vagrant,h4ck3rm1k3/vagrant,evverx/vagrant,pwnall/vagrant,miguel250/vagrant,janek-warchol/vagrant,iNecas/vagrant,philoserf/vagrant,vamegh/vagrant,gajdaw/vagrant,theist/vagrant,dharmab/vagrant,kalabiyau/vagrant,Chhed13/vagrant,petems/vagrant,dharmab/vagrant,theist/vagrant,mkuzmin/vagrant,mwrock/vagrant,PatOShea/vagrant,blueyed/vagrant,invernizzi-at-google/vagrant,wangfakang/vagrant,MiLk/vagrant,tbriggs-curse/vagrant,tbarrongh/vagrant,mwrock/vagrant,jtopper/vagrant,denisbr/vagrant,aaam/vagrant,stephancom/vagrant,otagi/vagrant,genome21/vagrant,mwarren/vagrant,philwrenn/vagrant,johntron/vagrant,benh57/vagrant,dhoer/vagrant,loren-osborn/vagrant,MiLk/vagrant,denisbr/vagrant,bshurts/vagrant,mwarren/vagrant,otagi/vagrant,chrisroberts/vagrant,gbarberi/vagrant,janek-warchol/vagrant,Chhed13/vagrant,chrisvire/vagrant,signed8bit/vagrant,crashlytics/vagrant,carlosefr/vagrant,Endika/vagrant,dustymabe/vagrant,ArloL/vagrant,jtopper/vagrant,ianmiell/vagrant,iNecas/vagrant,kamigerami/vagrant,senglin/vagrant,myrjola/vagrant,sax/vagrant,kamigerami/vagrant,gitebra/vagrant,fnewberg/vagrant,h4ck3rm1k3/vagrant,lukebakken/vagrant,teotihuacanada/vagrant,lukebakken/vagrant,justincampbell/vagrant,justincampbell/vagrant,myrjola/vagrant,crashlytics/vagrant,jmanero/vagrant,philwrenn/vagrant,lukebakken/vagrant,signed8bit/vagrant,benizi/vagrant,apertoso/vagrant,jean/vagrant,petems/vagrant,benizi/vagrant,jberends/vagrant,jean/vagrant,theist/vagrant,janek-warchol/vagrant,jean/vagrant,ianmiell/vagrant,chrisroberts/vagrant,dhoer/vagrant,theist/vagrant,juiceinc/vagrant,petems/vagrant,ferventcoder/vagrant,Avira/vagrant,mpoeter/vagrant,darkn3rd/vagrant,carlosefr/vagrant,taliesins/vagrant,shtouff/vagrant,kamazee/vagrant,dustymabe/vagrant,legal90/vagrant,h4ck3rm1k3/vagrant,invernizzi-at-google/vagrant,jberends/vagrant,patrys/vagrant,janek-warchol/vagrant,wkolean/vagrant,crashlytics/vagrant,jkburges/vagrant,taliesins/vagrant,rivy/vagrant,nickryand/vagrant,aaam/vagrant,zsjohny/vagrant,bryson/vagrant,miguel250/vagrant,tjanez/vagrant,gitebra/vagrant,zsjohny/vagrant,bdwyertech/vagrant,clinstid/vagrant,ArloL/vagrant,marxarelli/vagrant,modulexcite/vagrant,TheBigBear/vagrant,jhoblitt/vagrant,blueyed/vagrant,tbriggs-curse/vagrant,tknerr/vagrant,tomfanning/vagrant,sideci-sample/sideci-sample-vagrant,nickryand/vagrant,muhanadra/vagrant,nickryand/vagrant,Chhunlong/vagrant,mitchellh/vagrant,tomfanning/vagrant,Chhunlong/vagrant,Sgoettschkes/vagrant,doy/vagrant,pwnall/vagrant,jtopper/vagrant,h4ck3rm1k3/vagrant,otagi/vagrant,myrjola/vagrant,muhanadra/vagrant,benizi/vagrant,muhanadra/vagrant,taliesins/vagrant,channui/vagrant,jtopper/vagrant,nickryand/vagrant,muhanadra/vagrant,tbarrongh/vagrant,sideci-sample/sideci-sample-vagrant,PatrickLang/vagrant,kalabiyau/vagrant,tbriggs-curse/vagrant,kalabiyau/vagrant,gbarberi/vagrant,mitchellh/vagrant,obnoxxx/vagrant,channui/vagrant,jfchevrette/vagrant,tjanez/vagrant,obnoxxx/vagrant,cgvarela/vagrant,gbarberi/vagrant,tbarrongh/vagrant,ianmiell/vagrant,patrys/vagrant,crashlytics/vagrant,jhoblitt/vagrant,tknerr/vagrant,loren-osborn/vagrant,sax/vagrant,mkuzmin/vagrant,tschortsch/vagrant,sni/vagrant,bryson/vagrant,stephancom/vagrant,aneeshusa/vagrant,bryson/vagrant,krig/vagrant,jhoblitt/vagrant,mpoeter/vagrant,sideci-sample/sideci-sample-vagrant,Sgoettschkes/vagrant,teotihuacanada/vagrant,iNecas/vagrant,denisbr/vagrant,vamegh/vagrant,sni/vagrant,darkn3rd/vagrant,bshurts/vagrant,apertoso/vagrant,genome21/vagrant,bheuvel/vagrant,tschortsch/vagrant,wkolean/vagrant,lonniev/vagrant,jmanero/vagrant,evverx/vagrant,mpoeter/vagrant,wangfakang/vagrant,legal90/vagrant,gbarberi/vagrant,krig/vagrant,carlosefr/vagrant,genome21/vagrant,wkolean/vagrant,stephancom/vagrant,wangfakang/vagrant,cgvarela/vagrant,Chhunlong/vagrant,ianmiell/vagrant,Endika/vagrant,zsjohny/vagrant,TheBigBear/vagrant,lonniev/vagrant,philoserf/vagrant,ferventcoder/vagrant,vamegh/vagrant,gpkfr/vagrant,tbriggs-curse/vagrant,mkuzmin/vagrant,juiceinc/vagrant,krig/vagrant,sax/vagrant,dhoer/vagrant,blueyed/vagrant,stephancom/vagrant,kamigerami/vagrant,apertoso/vagrant,legal90/vagrant,mwrock/vagrant,benh57/vagrant,tschortsch/vagrant,marxarelli/vagrant,mkuzmin/vagrant,otagi/vagrant,jberends/vagrant,wkolean/vagrant,aneeshusa/vagrant,jberends/vagrant,PatOShea/vagrant,invernizzi-at-google/vagrant,fnewberg/vagrant,rivy/vagrant,kamazee/vagrant,juiceinc/vagrant,doy/vagrant,PatrickLang/vagrant,jfchevrette/vagrant,Chhed13/vagrant,ArloL/vagrant,jfchevrette/vagrant,bryson/vagrant,johntron/vagrant,ferventcoder/vagrant,bheuvel/vagrant,jkburges/vagrant,PatOShea/vagrant,justincampbell/vagrant,mwarren/vagrant,gpkfr/vagrant,chrisvire/vagrant,sni/vagrant,senglin/vagrant,sni/vagrant,bheuvel/vagrant,aaam/vagrant,bdwyertech/vagrant,sax/vagrant,rivy/vagrant,signed8bit/vagrant,myrjola/vagrant,dharmab/vagrant,Avira/vagrant,legal90/vagrant,gajdaw/vagrant,Endika/vagrant,jhoblitt/vagrant,pwnall/vagrant,tjanez/vagrant,jmanero/vagrant,gitebra/vagrant,dustymabe/vagrant,mitchellh/vagrant,mpoeter/vagrant,tjanez/vagrant,denisbr/vagrant,rivy/vagrant,evverx/vagrant,gpkfr/vagrant,patrys/vagrant,jkburges/vagrant,jean/vagrant,dharmab/vagrant,benh57/vagrant,signed8bit/vagrant,mitchellh/vagrant,bshurts/vagrant,Avira/vagrant,Sgoettschkes/vagrant,tomfanning/vagrant,benizi/vagrant,ferventcoder/vagrant,tbarrongh/vagrant,marxarelli/vagrant,zsjohny/vagrant,gajdaw/vagrant,bdwyertech/vagrant,gitebra/vagrant,doy/vagrant,cgvarela/vagrant,obnoxxx/vagrant,teotihuacanada/vagrant,jmanero/vagrant,lonniev/vagrant,philoserf/vagrant,tknerr/vagrant,johntron/vagrant,modulexcite/vagrant,justincampbell/vagrant,pwnall/vagrant,philwrenn/vagrant,jkburges/vagrant,lonniev/vagrant,genome21/vagrant,Avira/vagrant,johntron/vagrant,fnewberg/vagrant,modulexcite/vagrant,blueyed/vagrant,kalabiyau/vagrant,miguel250/vagrant,clinstid/vagrant,shtouff/vagrant,dhoer/vagrant,Sgoettschkes/vagrant,MiLk/vagrant,chrisvire/vagrant,loren-osborn/vagrant,juiceinc/vagrant,bheuvel/vagrant,Endika/vagrant,Chhunlong/vagrant,doy/vagrant,aneeshusa/vagrant,dustymabe/vagrant,chrisroberts/vagrant