Mark working instances as working in rss_to_timeline().

rss.c

@@ -281,6 +281,9 @@ void rss_to_timeline(snac *user, const char *url)
             if (!xs_match(type, POSTLIKE_OBJECT_TYPE))
                 continue;
 
+            /* the instance is [back] online */
+            instance_failure(object, 2);
+
             if (timeline_here(user, id)) {
                 snac_debug(user, 1, xs_fmt("RSS entry already in timeline (id) %s", id));
                 continue;