fix: pgsqlSetNoticeCallback: potential memory leak

Discard non-null result of callback.

Author: outtersg

ext/pdo_pgsql/pgsql_driver.c

@@ -120,7 +120,9 @@ static void _pdo_pgsql_notice(pdo_dbh_t *dbh, const char *message) /* {{{ */
 		fc->fci.param_count = 1;
 		fc->fci.params = &zarg;
 		fc->fci.retval = &retval;
-		ret = zend_call_function(&fc->fci, &fc->fcc TSRMLS_CC);
+		if ((ret = zend_call_function(&fc->fci, &fc->fcc TSRMLS_CC)) != FAILURE) {
+			zval_ptr_dtor(&retval);
+		}
 		zval_ptr_dtor(&zarg);
 		if (ret == FAILURE) {
 			pdo_raise_impl_error(dbh, NULL, "HY000", "could not call user-supplied function" TSRMLS_CC);