Update precommit hook to avoid python reordering

If a conformance directory existed in the base of the repository,
the reorder-python-imports hook would move import lines around.
Feed it a dummy directory to avoid it considering any file an
application file

Signed-off-by: Eric Kunze <eric.kunze@arm.com>
Change-Id: Ic3700a9b0f43965222a72fb4a386c6a0d7ec4c4a