tests/kms_flip: don't leak the connector when setting DPMS

Caught by Valgrind.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>

tests/kms_flip.c

@@ -295,6 +295,8 @@ static void dpms_off_other_outputs(struct test_output *o)
 
 		set_connector_dpms(connector,  DRM_MODE_DPMS_ON);
 		set_connector_dpms(connector,  DRM_MODE_DPMS_OFF);
+
+		drmModeFreeConnector(connector);
 next:
 		;
 	}