Bugfix in init re prefix

src/ttail.c

@@ -221,6 +221,7 @@ int ttail_set_prefix(ttail_t* res, const char* regex)
 		return 0;
 	}
 	/*compilation error */
+	res->flag ^= TTAIL_FLAG_PREFIX;
 	re_errbuff_sz = regerror(ret,
 		&res->date_prefix, NULL, 0);
 	re_errbuff = malloc(