[471334] Fix incorrect loop timeout with keepalive=0.

Fix incorrect loop timeout being chosen when using the threaded
interface and keepalive = 0.

Thanks to Gianfranco Costamagna.

Bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=471334

ChangeLog.txt

@@ -5,6 +5,8 @@ Broker:
 Client library:
 - Add missing error strings to mosquitto_strerror.
 - Handle fragmented TLS packets without a delay. Closes #470660.
+- Fix incorrect loop timeout being chosen when using threaded interface and
+  keepalive = 0. Closes #471334.
 
 Clients:
 - Report error string on connection failure rather than error code.

lib/thread_mosq.c

@@ -89,7 +89,7 @@ void *_mosquitto_thread_main(void *obj)
 
 	if(!mosq->keepalive){
 		/* Sleep for a day if keepalive disabled. */
-		mosquitto_loop_forever(mosq, mosq->keepalive*1000*86400, 1);
+		mosquitto_loop_forever(mosq, 1000*86400, 1);
 	}else{
 		/* Sleep for our keepalive value. publish() etc. will wake us up. */
 		mosquitto_loop_forever(mosq, mosq->keepalive*1000, 1);