Cleanup path joining.
Cleanup path joining.

This cleans up the path joining to prevent the rare case of seeing paths
with // in them. This didn't cause any harm, but now the code is
cleaner, and users won't see this ugly path double. This gives people
more confidence that we care about not deleting their files.

LalatenduMohanty/oh-my-vagrant,goern/oh-my-vagrant,bhalothia/oh-my-vagrant,mairin/oh-my-vagrant,goern/oh-my-vagrant,br0ziliy/oh-my-vagrant,bhalothia/oh-my-vagrant,purpleidea/oh-my-vagrant,geekcheng/oh-my-vagrant,geekcheng/oh-my-vagrant,ncoghlan/oh-my-vagrant,purpleidea/oh-my-vagrant,br0ziliy/oh-my-vagrant,LalatenduMohanty/oh-my-vagrant,mairin/oh-my-vagrant,LalatenduMohanty/oh-my-vagrant,br0ziliy/oh-my-vagrant,gpjonesii/oh-my-vagrant,bhalothia/oh-my-vagrant,mairin/oh-my-vagrant,geekcheng/oh-my-vagrant,goern/oh-my-vagrant,gpjonesii/oh-my-vagrant,ncoghlan/oh-my-vagrant,purpleidea/oh-my-vagrant,gpjonesii/oh-my-vagrant