Fix REPL failures with Linenoise
Fix REPL failures with Linenoise

Bug find: https://irclog.perlgeek.de/perl6/2017-04-19#i_14452772

The code for creating paths starts off by trying to `mkdir` `/` dir
and so on for each path. On OSX, this fails, despite working fine on
Linux. Also, `mkdir` used to return the list of files, but not it
returns the Failure object, 'causing the explosion.

Fix by removing all the mkpath business, because mkdir is `mkdir -p`
really. And then watch out for Failures from mkdir.

softmoth/rakudo,tony-o/rakudo,sjn/rakudo,labster/rakudo,sjn/rakudo,lucasbuchala/rakudo,rakudo/rakudo,jonathanstowe/rakudo,MasterDuke17/rakudo,raydiak/rakudo,salortiz/rakudo,Gnouc/rakudo,nbrown/rakudo,lucasbuchala/rakudo,tbrowder/rakudo,tbrowder/rakudo,softmoth/rakudo,awwaiid/rakudo,Gnouc/rakudo,tony-o/rakudo,salortiz/rakudo,softmoth/rakudo,MasterDuke17/rakudo,tbrowder/rakudo,awwaiid/rakudo,rakudo/rakudo,nbrown/rakudo,sjn/rakudo,jonathanstowe/rakudo,nbrown/rakudo,lucasbuchala/rakudo,labster/rakudo,salortiz/rakudo,softmoth/rakudo,tony-o/rakudo,salortiz/rakudo,tbrowder/rakudo,labster/rakudo,nbrown/rakudo,awwaiid/rakudo,awwaiid/rakudo,tony-o/rakudo,labster/rakudo,sjn/rakudo,Gnouc/rakudo,raydiak/rakudo,raydiak/rakudo,salortiz/rakudo,lucasbuchala/rakudo,lucasbuchala/rakudo,usev6/rakudo,jonathanstowe/rakudo,raydiak/rakudo,jonathanstowe/rakudo,rakudo/rakudo,salortiz/rakudo,Gnouc/rakudo,MasterDuke17/rakudo,MasterDuke17/rakudo,softmoth/rakudo,MasterDuke17/rakudo,labster/rakudo,nbrown/rakudo,awwaiid/rakudo,tony-o/rakudo,rakudo/rakudo,rakudo/rakudo,sjn/rakudo,Gnouc/rakudo,MasterDuke17/rakudo,tony-o/rakudo,rakudo/rakudo,usev6/rakudo,usev6/rakudo,usev6/rakudo,jonathanstowe/rakudo,Gnouc/rakudo,nbrown/rakudo,tbrowder/rakudo,labster/rakudo,tbrowder/rakudo,usev6/rakudo