test/mock: remove force power in finalize

If the force power device has not yet been removed, do so in the
'finalize' method of the MockSysfs object. Move the un-ref'ing of
the umockdev TestBed down so it happens after the hash tables
are destroyed.

tests/mock-sysfs.c

@@ -144,10 +144,14 @@ mock_sysfs_finalize (GObject *object)
 {
   MockSysfs *ms = MOCK_SYSFS (object);
 
-  g_clear_object (&ms->bed);
+  if (ms->force_power)
+    mock_sysfs_force_power_remove (ms);
+
   g_clear_pointer (&ms->domains, g_hash_table_unref);
   g_clear_pointer (&ms->devices, g_hash_table_unref);
 
+  g_clear_object (&ms->bed);
+
   G_OBJECT_CLASS (mock_sysfs_parent_class)->finalize (object);
 }