trackrdrd: add a write memory barrier after all data is copied from

           the Varnish log to a record

trackrdrd/src/child.c

@@ -816,6 +816,7 @@ OSL_Track(void *priv, enum VSL_tag_e tag, unsigned fd, unsigned len,
         sprintf(reqend_str, "%s=%u.%09lu", REQEND_T_VAR,
             (unsigned) reqend_t.tv_sec, reqend_t.tv_nsec);
         append(de, tag, xid, reqend_str, strlen(reqend_str));
+        VWMB();
         de->state = DATA_DONE;
         MON_StatsUpdate(STATS_DONE);
         submit(he);