avoid extra LOG_NOTICE for every new microdesc batch

We already write out bootstrapping progress (see bug 9927) per new
microdesc batch. There's no need to do a full "I learned some more
directory information, but not enough to..." line each time too.

src/or/directory.c

@@ -2169,7 +2169,7 @@ connection_dir_client_reached_eof(dir_connection_t *conn)
       control_event_bootstrap(BOOTSTRAP_STATUS_LOADING_DESCRIPTORS,
                               count_loading_descriptors_progress());
       if (mds && smartlist_len(mds))
-        directory_info_has_arrived(now, 0, 0);
+        directory_info_has_arrived(now, 0, 1);
       SMARTLIST_FOREACH(which, char *, cp, tor_free(cp));
       smartlist_free(which);
       smartlist_free(mds);