Get file_manager working via ugly hack

Created by: NilSet

Problem: file_manager app can't go up into parent directories

Solution: trim the leading file: from the path returned by get_parent_directory

Drawbacks: Doesn't address the fact that something somewhere isn't handling paths with the scheme on them correctly.

TODOs: Find out where the bug really is.

Fixes: #644 (closed)

State: Ready