Implement resync after update monitor reconnect

src/service/interface/dbusservice.vala

@@ -53,6 +53,9 @@ namespace DBusService {
 		[DBus (name = "MessagesUpdated")]
 		public signal void messages_updated(string conversation_id);
 
+		[DBus (name = "UpdateStreamReconnected")]
+		public signal void update_stream_reconnected();
+
 		[DBus (name = "GetAttachmentInfo")]
 		public abstract RepositoryAttachmentInfoStruct get_attachment_info(string attachment_id) throws DBusError, IOError;