providers/virtualbox: make sure sf host paths are strings
providers/virtualbox: make sure sf host paths are strings

jfchevrette/vagrant,shtouff/vagrant,myrjola/vagrant,myrjola/vagrant,ferventcoder/vagrant,benh57/vagrant,mpoeter/vagrant,benizi/vagrant,legal90/vagrant,mpoeter/vagrant,gbarberi/vagrant,clinstid/vagrant,senglin/vagrant,channui/vagrant,bshurts/vagrant,zsjohny/vagrant,vamegh/vagrant,jean/vagrant,h4ck3rm1k3/vagrant,sax/vagrant,tschortsch/vagrant,rivy/vagrant,bshurts/vagrant,invernizzi-at-google/vagrant,Chhunlong/vagrant,sax/vagrant,Endika/vagrant,cgvarela/vagrant,ianmiell/vagrant,tbriggs-curse/vagrant,jhoblitt/vagrant,sideci-sample/sideci-sample-vagrant,gbarberi/vagrant,krig/vagrant,aneeshusa/vagrant,obnoxxx/vagrant,p0deje/vagrant,philoserf/vagrant,nickryand/vagrant,mitchellh/vagrant,loren-osborn/vagrant,vamegh/vagrant,iNecas/vagrant,aaam/vagrant,taliesins/vagrant,muhanadra/vagrant,janek-warchol/vagrant,blueyed/vagrant,wkolean/vagrant,bdwyertech/vagrant,BlakeMesdag/vagrant,lukebakken/vagrant,crashlytics/vagrant,janek-warchol/vagrant,doy/vagrant,bdwyertech/vagrant,janek-warchol/vagrant,doy/vagrant,crashlytics/vagrant,shtouff/vagrant,wangfakang/vagrant,petems/vagrant,darkn3rd/vagrant,aneeshusa/vagrant,mkuzmin/vagrant,sferik/vagrant,miguel250/vagrant,taliesins/vagrant,dustymabe/vagrant,theist/vagrant,fnewberg/vagrant,wkolean/vagrant,evverx/vagrant,genome21/vagrant,Chhed13/vagrant,carlosefr/vagrant,marxarelli/vagrant,mitchellh/vagrant,lonniev/vagrant,chrisvire/vagrant,teotihuacanada/vagrant,modulexcite/vagrant,juiceinc/vagrant,krig/vagrant,philwrenn/vagrant,gajdaw/vagrant,jberends/vagrant,senglin/vagrant,signed8bit/vagrant,sideci-sample/sideci-sample-vagrant,teotihuacanada/vagrant,gpkfr/vagrant,genome21/vagrant,apertoso/vagrant,tbriggs-curse/vagrant,mwarren/vagrant,obnoxxx/vagrant,channui/vagrant,jmanero/vagrant,sferik/vagrant,chrisvire/vagrant,Endika/vagrant,gbarberi/vagrant,TheBigBear/vagrant,wangfakang/vagrant,vamegh/vagrant,petems/vagrant,philwrenn/vagrant,PatOShea/vagrant,modulexcite/vagrant,wkolean/vagrant,signed8bit/vagrant,dharmab/vagrant,johntron/vagrant,tbarrongh/vagrant,carlosefr/vagrant,bshurts/vagrant,kalabiyau/vagrant,dustymabe/vagrant,tbarrongh/vagrant,petems/vagrant,mitchellh/vagrant,janek-warchol/vagrant,Ninir/vagrant,dhoer/vagrant,Avira/vagrant,miguel250/vagrant,mpoeter/vagrant,benizi/vagrant,fnewberg/vagrant,philoserf/vagrant,apertoso/vagrant,kamigerami/vagrant,jmanero/vagrant,gbarberi/vagrant,genome21/vagrant,mwrock/vagrant,kalabiyau/vagrant,patrys/vagrant,modulexcite/vagrant,jfchevrette/vagrant,blueyed/vagrant,jmanero/vagrant,otagi/vagrant,loren-osborn/vagrant,philoserf/vagrant,Chhed13/vagrant,denisbr/vagrant,lukebakken/vagrant,Ninir/vagrant,evverx/vagrant,invernizzi-at-google/vagrant,crashlytics/vagrant,darkn3rd/vagrant,cgvarela/vagrant,tomfanning/vagrant,bryson/vagrant,benh57/vagrant,juiceinc/vagrant,fnewberg/vagrant,loren-osborn/vagrant,BlakeMesdag/vagrant,jmanero/vagrant,jhoblitt/vagrant,bshurts/vagrant,gitebra/vagrant,p0deje/vagrant,gpkfr/vagrant,darkn3rd/vagrant,fnewberg/vagrant,legal90/vagrant,apertoso/vagrant,tjanez/vagrant,nickryand/vagrant,theist/vagrant,kamazee/vagrant,kalabiyau/vagrant,jberends/vagrant,h4ck3rm1k3/vagrant,ArloL/vagrant,philoserf/vagrant,zsjohny/vagrant,chrisroberts/vagrant,miguel250/vagrant,sax/vagrant,signed8bit/vagrant,wangfakang/vagrant,blueyed/vagrant,tomfanning/vagrant,apertoso/vagrant,jean/vagrant,Chhunlong/vagrant,tknerr/vagrant,stephancom/vagrant,PatOShea/vagrant,bryson/vagrant,cgvarela/vagrant,muhanadra/vagrant,dharmab/vagrant,mwrock/vagrant,miguel250/vagrant,taliesins/vagrant,carlosefr/vagrant,stephancom/vagrant,theist/vagrant,PatrickLang/vagrant,bheuvel/vagrant,chrisvire/vagrant,bryson/vagrant,Chhunlong/vagrant,dustymabe/vagrant,MiLk/vagrant,tbarrongh/vagrant,sni/vagrant,clinstid/vagrant,PatOShea/vagrant,teotihuacanada/vagrant,wangfakang/vagrant,doy/vagrant,darkn3rd/vagrant,shtouff/vagrant,BlakeMesdag/vagrant,pwnall/vagrant,dharmab/vagrant,senglin/vagrant,TheBigBear/vagrant,aneeshusa/vagrant,iNecas/vagrant,teotihuacanada/vagrant,ianmiell/vagrant,aaam/vagrant,tomfanning/vagrant,wkolean/vagrant,taliesins/vagrant,tomfanning/vagrant,Chhed13/vagrant,bheuvel/vagrant,jtopper/vagrant,otagi/vagrant,theist/vagrant,ianmiell/vagrant,carlosefr/vagrant,chrisroberts/vagrant,gpkfr/vagrant,jtopper/vagrant,patrys/vagrant,p0deje/vagrant,mwarren/vagrant,evverx/vagrant,doy/vagrant,krig/vagrant,jean/vagrant,gitebra/vagrant,mkuzmin/vagrant,vamegh/vagrant,genome21/vagrant,benh57/vagrant,johntron/vagrant,chrisvire/vagrant,kamigerami/vagrant,denisbr/vagrant,myrjola/vagrant,rivy/vagrant,TheBigBear/vagrant,kamazee/vagrant,patrys/vagrant,ferventcoder/vagrant,jberends/vagrant,marxarelli/vagrant,aaam/vagrant,kamigerami/vagrant,Sgoettschkes/vagrant,petems/vagrant,myrjola/vagrant,Sgoettschkes/vagrant,tschortsch/vagrant,ferventcoder/vagrant,lukebakken/vagrant,tknerr/vagrant,benh57/vagrant,tbriggs-curse/vagrant,aaam/vagrant,jhoblitt/vagrant,tbarrongh/vagrant,justincampbell/vagrant,jkburges/vagrant,rivy/vagrant,lonniev/vagrant,sideci-sample/sideci-sample-vagrant,Sgoettschkes/vagrant,jtopper/vagrant,marxarelli/vagrant,dhoer/vagrant,TheBigBear/vagrant,invernizzi-at-google/vagrant,blueyed/vagrant,marxarelli/vagrant,sax/vagrant,ArloL/vagrant,PatrickLang/vagrant,juiceinc/vagrant,mkuzmin/vagrant,jkburges/vagrant,philwrenn/vagrant,signed8bit/vagrant,Chhed13/vagrant,sni/vagrant,Ninir/vagrant,benizi/vagrant,jkburges/vagrant,kamazee/vagrant,tjanez/vagrant,ArloL/vagrant,pwnall/vagrant,benizi/vagrant,mwrock/vagrant,crashlytics/vagrant,jhoblitt/vagrant,tjanez/vagrant,MiLk/vagrant,jtopper/vagrant,nickryand/vagrant,h4ck3rm1k3/vagrant,tjanez/vagrant,johntron/vagrant,tschortsch/vagrant,justincampbell/vagrant,gpkfr/vagrant,justincampbell/vagrant,denisbr/vagrant,Endika/vagrant,muhanadra/vagrant,stephancom/vagrant,Chhunlong/vagrant,chrisroberts/vagrant,Avira/vagrant,shtouff/vagrant,bheuvel/vagrant,ferventcoder/vagrant,tbriggs-curse/vagrant,otagi/vagrant,lukebakken/vagrant,kamigerami/vagrant,tschortsch/vagrant,gitebra/vagrant,stephancom/vagrant,ArloL/vagrant,mkuzmin/vagrant,chrisroberts/vagrant,jkburges/vagrant,jean/vagrant,kalabiyau/vagrant,mwarren/vagrant,gajdaw/vagrant,lonniev/vagrant,mwarren/vagrant,justincampbell/vagrant,invernizzi-at-google/vagrant,Sgoettschkes/vagrant,pwnall/vagrant,legal90/vagrant,dustymabe/vagrant,bdwyertech/vagrant,bryson/vagrant,jfchevrette/vagrant,jfchevrette/vagrant,dhoer/vagrant,nickryand/vagrant,Avira/vagrant,sni/vagrant,h4ck3rm1k3/vagrant,mwrock/vagrant,zsjohny/vagrant,gitebra/vagrant,rivy/vagrant,senglin/vagrant,tknerr/vagrant,MiLk/vagrant,cgvarela/vagrant,PatOShea/vagrant,lonniev/vagrant,zsjohny/vagrant,gajdaw/vagrant,muhanadra/vagrant,otagi/vagrant,PatrickLang/vagrant,aneeshusa/vagrant,krig/vagrant,sni/vagrant,sferik/vagrant,jberends/vagrant,philwrenn/vagrant,mitchellh/vagrant,Avira/vagrant,patrys/vagrant,loren-osborn/vagrant,Endika/vagrant,mpoeter/vagrant,pwnall/vagrant,modulexcite/vagrant,iNecas/vagrant,kamazee/vagrant,obnoxxx/vagrant,tknerr/vagrant,denisbr/vagrant,legal90/vagrant,bheuvel/vagrant,channui/vagrant,juiceinc/vagrant,bdwyertech/vagrant,dhoer/vagrant,clinstid/vagrant,dharmab/vagrant,PatrickLang/vagrant,johntron/vagrant,ianmiell/vagrant