Fix error codes not being returned when mosquitto_pub exits.

Closes #1354. Thanks to Ben Barbour.

ChangeLog.txt

@@ -11,6 +11,10 @@ Client library:
 - Fix MQTT v5 subscription options being incorrectly set for MQTT v3
   subscriptions. Closes #1353.
 
+Clients:
+- mosquitto_pub: fix error codes not being returned when mosquitto_pub exits.
+  Closes #1354.
+
 
 1.6.3 - 20190618
 ================

client/pub_client.c

@@ -103,7 +103,9 @@ void my_disconnect_callback(struct mosquitto *mosq, void *obj, int rc, const mos
 	UNUSED(rc);
 	UNUSED(properties);
 
+	if(rc == 0){
 		status = STATUS_DISCONNECTED;
+	}
 }
 
 int my_publish(struct mosquitto *mosq, int *mid, const char *topic, int payloadlen, void *payload, int qos, bool retain)