[PBCKP-382] version 15 compatibility bug

Author: Daniel Shelepanov

tests/auth_test.py

@@ -140,7 +140,6 @@ def test_backup_via_unprivileged_user(self):
         else:
             node.safe_psql(
                 "postgres",
-                "GRANT EXECUTE ON FUNCTION pg_backup_stop() TO backup; "
                 "GRANT EXECUTE ON FUNCTION pg_backup_stop(boolean) TO backup;")
 
         self.backup_node(