[horde] VFS "file" backend, relative paths and gollem's "change directory"

[Liam Hoekenga]

> Yeah, ~/test worked fine for me just now.

But what about like... trying subdir1/subdir2 (assuming you're in the top level
of your home directory, and ~/subdir1/subdir2 exists?).  That did work with
1.44, but not 1.50..

Liam