Fix bridges not sending failure notification messages.

This is for messages to the local broker if the remote bridge connection
fails.

Closes #1488.
Closes #2467.

ChangeLog.txt

@@ -13,6 +13,8 @@ Broker:
   Closes #2404.
 - Add clients to session expiry check list when restarting and reloading from
   persistence. Closes #2546.
+- Fix bridges not sending failure notification messages to the local broker if
+  the remote bridge connection fails. Closes #2467. Closes #1488.
 
 Client library:
 - Fix threads library detection on Windows under cmake. Bumps the minimum

lib/util_mosq.c

@@ -104,6 +104,12 @@ int mosquitto__check_keepalive(struct mosquitto *mosq)
 			pthread_mutex_unlock(&mosq->msgtime_mutex);
 		}else{
 #ifdef WITH_BROKER
+#  ifdef WITH_BRIDGE
+			if(mosq->bridge){
+				context__send_will(mosq);
+			}
+#  endif
+#endif
 			net__socket_close(mosq);
 #else
 			net__socket_close(mosq);