use portable unlink in delete_walfiles_in_tli()

src/delete.c

@@ -933,7 +933,7 @@ delete_walfiles_in_tli(XLogRecPtr keep_lsn, timelineInfo *tlinfo,
 			}
 
 			/* unlink segment */
-			rc = unlink(wal_file->file.path);
+			rc = fio_unlink(wal_file->file.path, FIO_BACKUP_HOST);
 			if (rc < 0)
 			{
 				/* Missing file is not considered as error condition */

src/utils/file.c

@@ -816,6 +816,7 @@ int fio_unlink(char const* path, fio_location location)
 		IO_CHECK(fio_write_all(fio_stdout, &hdr, sizeof(hdr)), sizeof(hdr));
 		IO_CHECK(fio_write_all(fio_stdout, path, path_len), path_len);
 
+		// TODO: error is swallowed ?
 		return 0;
 	}
 	else