trivial: Use fwupd_device_add_flags() to set a single flag

libfwupd/fwupd-self-test.c

@@ -330,7 +330,7 @@ fwupd_device_func (void)
 	dev = fwupd_device_new ();
 	fwupd_device_add_checksum (dev, "beefdead");
 	fwupd_device_set_created (dev, 1);
-	fwupd_device_set_flags (dev, FWUPD_DEVICE_FLAG_UPDATABLE);
+	fwupd_device_add_flag (dev, FWUPD_DEVICE_FLAG_UPDATABLE);
 	fwupd_device_set_id (dev, "USB:foo");
 	fwupd_device_set_modified (dev, 60 * 60 * 24);
 	fwupd_device_set_name (dev, "ColorHug2");

src/fu-self-test.c

@@ -2652,7 +2652,7 @@ fu_history_func (gconstpointer user_data)
 	fu_device_set_update_state (device, FWUPD_UPDATE_STATE_FAILED);
 	fu_device_set_update_error (device, "word");
 	fu_device_add_guid (device, "827edddd-9bb6-5632-889f-2c01255503da");
-	fu_device_set_flags (device, FWUPD_DEVICE_FLAG_INTERNAL);
+	fu_device_add_flag (device, FWUPD_DEVICE_FLAG_INTERNAL);
 	fu_device_set_created (device, 123);
 	fu_device_set_modified (device, 456);
 	release = fwupd_release_new ();