Fix packs views files controller to use pack ref when determing pack directory name.
Fix packs views files controller to use pack ref when determing pack
directory name.

Pack directory names matches ref and not name so it won't work if we use
name.

tonybaloney/st2,nzlosh/st2,Plexxi/st2,StackStorm/st2,tonybaloney/st2,peak6/st2,Plexxi/st2,nzlosh/st2,StackStorm/st2,StackStorm/st2,StackStorm/st2,peak6/st2,nzlosh/st2,peak6/st2,Plexxi/st2,nzlosh/st2,Plexxi/st2,tonybaloney/st2