remove an easy TODO in render_group (add rgFree() before return)

src/render_group.cpp

@@ -128,9 +128,10 @@ rgInitEntity(Entity* e)
 		if (rg->render_objects[i] == nullptr)
 			return false;
 
-		// TODO: safely free memory here when convertMeshInfo returns false
-		if (!convertMeshInfo(e->mesh_group.meshes[i], rg->render_objects[i], rg->use_normals))
+		if (!convertMeshInfo(e->mesh_group.meshes[i], rg->render_objects[i], rg->use_normals)) {
+			rgFree(rg);
 			return false;
+		}
 	}
 
 	return true;