zbar_pipeline: fix memory leak, when pixel format is unsupported

src/zbar_pipeline.c

@@ -241,6 +241,8 @@ process_image(MPPipeline *pipeline, MPZBarImage **_image)
                         break;
                 default:
                         printf("Preview pixel format not supported - zbar won't work\n");
+			free(data);
+			mp_zbar_image_unref(image);
                         return;
         }