Fix warning on unset HOME env variables
Fix warning on unset HOME env variables

Inspired by pull request #334 (carbin++).  This approach has fewer dynamic
variable lookups than the pull request.

nunorc/rakudo,sjn/rakudo,teodozjan/rakudo,nbrown/rakudo,LLFourn/rakudo,lucasbuchala/rakudo,paultcochrane/rakudo,ugexe/rakudo,LLFourn/rakudo,Leont/rakudo,nbrown/rakudo,dankogai/rakudo,lucasbuchala/rakudo,Gnouc/rakudo,awwaiid/rakudo,zostay/rakudo,tony-o/deb-rakudodaily,jonathanstowe/rakudo,sjn/rakudo,raydiak/rakudo,ugexe/rakudo,tbrowder/rakudo,cygx/rakudo,niner/rakudo,b2gills/rakudo,tbrowder/rakudo,tony-o/deb-rakudodaily,Gnouc/rakudo,ab5tract/rakudo,laben/rakudo,awwaiid/rakudo,ungrim97/rakudo,usev6/rakudo,zhuomingliang/rakudo,sjn/rakudo,nbrown/rakudo,paultcochrane/rakudo,zostay/rakudo,tony-o/rakudo,paultcochrane/rakudo,MasterDuke17/rakudo,raydiak/rakudo,awwaiid/rakudo,nunorc/rakudo,jonathanstowe/rakudo,ab5tract/rakudo,niner/rakudo,tony-o/deb-rakudodaily,cognominal/rakudo,samcv/rakudo,labster/rakudo,tony-o/rakudo,zostay/rakudo,niner/rakudo,ab5tract/rakudo,tony-o/rakudo,nbrown/rakudo,samcv/rakudo,zostay/rakudo,softmoth/rakudo,Leont/rakudo,salortiz/rakudo,lucasbuchala/rakudo,tbrowder/rakudo,skids/rakudo,zhuomingliang/rakudo,MasterDuke17/rakudo,samcv/rakudo,softmoth/rakudo,laben/rakudo,labster/rakudo,LLFourn/rakudo,rakudo/rakudo,awwaiid/rakudo,azawawi/rakudo,teodozjan/rakudo,skids/rakudo,labster/rakudo,softmoth/rakudo,LLFourn/rakudo,niner/rakudo,paultcochrane/rakudo,tbrowder/rakudo,ab5tract/rakudo,retupmoca/rakudo,tony-o/deb-rakudodaily,usev6/rakudo,skids/rakudo,nbrown/rakudo,Gnouc/rakudo,lucasbuchala/rakudo,usev6/rakudo,rakudo/rakudo,Leont/rakudo,tbrowder/rakudo,rakudo/rakudo,retupmoca/rakudo,ungrim97/rakudo,softmoth/rakudo,azawawi/rakudo,paultcochrane/rakudo,ungrim97/rakudo,ugexe/rakudo,skids/rakudo,b2gills/rakudo,cygx/rakudo,zhuomingliang/rakudo,awwaiid/rakudo,sergot/rakudo,jonathanstowe/rakudo,tony-o/deb-rakudodaily,cognominal/rakudo,salortiz/rakudo,ab5tract/rakudo,cygx/rakudo,nbrown/rakudo,b2gills/rakudo,cygx/rakudo,sjn/rakudo,usev6/rakudo,MasterDuke17/rakudo,dankogai/rakudo,LLFourn/rakudo,cognominal/rakudo,salortiz/rakudo,rakudo/rakudo,Leont/rakudo,MasterDuke17/rakudo,tony-o/rakudo,b2gills/rakudo,cygx/rakudo,raydiak/rakudo,tony-o/rakudo,tony-o/deb-rakudodaily,tony-o/rakudo,tony-o/deb-rakudodaily,nunorc/rakudo,samcv/rakudo,labster/rakudo,MasterDuke17/rakudo,ungrim97/rakudo,labster/rakudo,sjn/rakudo,ugexe/rakudo,dankogai/rakudo,azawawi/rakudo,Gnouc/rakudo,cognominal/rakudo,salortiz/rakudo,b2gills/rakudo,rakudo/rakudo,rakudo/rakudo,ugexe/rakudo,teodozjan/rakudo,Gnouc/rakudo,sergot/rakudo,laben/rakudo,jonathanstowe/rakudo,ungrim97/rakudo,cognominal/rakudo,MasterDuke17/rakudo,labster/rakudo,softmoth/rakudo,sergot/rakudo,Gnouc/rakudo,teodozjan/rakudo,retupmoca/rakudo,salortiz/rakudo,dankogai/rakudo,nunorc/rakudo,lucasbuchala/rakudo,samcv/rakudo,salortiz/rakudo,sergot/rakudo,usev6/rakudo,zhuomingliang/rakudo,skids/rakudo,azawawi/rakudo,azawawi/rakudo,jonathanstowe/rakudo,retupmoca/rakudo,dankogai/rakudo,tbrowder/rakudo,raydiak/rakudo,laben/rakudo