lib-storage: Fix mailbox list index notifications when modseqs aren't…

… enabled.

No notifications were sent if highest_modseqs weren't updated in mailbox
list index.

src/lib-storage/list/mailbox-list-index-notify.c

@@ -716,18 +716,14 @@ mailbox_list_index_notify_change(struct mailbox_list_notify_index *inotify,
 		rec->events |= MAILBOX_LIST_NOTIFY_SEEN_CHANGES;
 	if (nnode->highest_modseq < status.highest_modseq)
 		rec->events |= MAILBOX_LIST_NOTIFY_MODSEQ_CHANGES;
-	else {
-		/* nothing changed */
-		return FALSE;
-	}
 
 	/* update internal state */
 	nnode->uidvalidity = status.uidvalidity;
 	nnode->uidnext = status.uidnext;
 	nnode->messages = status.messages;
 	nnode->unseen = status.unseen;
 	nnode->highest_modseq = status.highest_modseq;
-	return TRUE;
+	return rec->events != 0;
 }
 
 static bool