Correctly exit dump on error.

This is a backup-breaking failure and the dump should exit rather than
simply breaking from the loop.

src/bin/pg_dump/cdb/cdb_ddboost_util.c

@@ -1396,7 +1396,7 @@ writeToDDFile(FILE *fp, char *ddBoostFileName, char *ddboost_storage_unit)
 		{
 			mpp_err_msg(logError, progname, "ddboost write failed on %s with err %d\n", path1.path_name, err);
 			err = -1;
-			break;
+			goto cleanup;
 		}
 
 		total_bytes += ret_count;