providers/virtualbox: only clear shared folders if we have a VM
providers/virtualbox: only clear shared folders if we have a VM

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