tests: Restore check-qdict unit test

Commit 0bcc8e5b accidentally dropped check-qdict from the list of
unit tests (again, see commit 4429532b).  Put it back, and fix up
the test.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180926122309.30631-1-armbru@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>