Fixed file completion for paths that start with '~'.

We didn't add the remaining path behind the '~' to the completion string,
causing it to just complete directories inside the user home directory. This
patch just adds the directory of the remaining path if there is one.

Fixes rdar://problem/40147002

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@334978 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed