Fix MQTT v5 sub opts being set for v3 subs.

Closes #1353. Thanks to Ben Barbour.

ChangeLog.txt

@@ -7,6 +7,10 @@ Broker:
 - Windows: Allow other applications access to the log file when running.
   Closes #515.
 
+Client library:
+- Fix MQTT v5 subscription options being incorrectly set for MQTT v3
+  subscriptions. Closes #1353.
+
 
 1.6.3 - 20190618
 ================

lib/actions.c

@@ -200,6 +200,9 @@ int mosquitto_subscribe_multiple(struct mosquitto *mosq, int *mid, int sub_count
 			return MOSQ_ERR_OVERSIZE_PACKET;
 		}
 	}
+	if(mosq->protocol == mosq_p_mqtt311 || mosq->protocol == mosq_p_mqtt31){
+		options = 0;
+	}
 
 	return send__subscribe(mosq, mid, sub_count, sub, qos|options, outgoing_properties);
 }

lib/mosquitto.h

@@ -921,8 +921,9 @@ libmosq_EXPORT int mosquitto_subscribe_v5(struct mosquitto *mosq, int *mid, cons
  *	       familiar with this, just think of it as a safer "char **",
  *	       equivalent to "const char *" for a simple string pointer.
  *	qos -  the requested Quality of Service for each subscription.
- *	options - options to apply to this subscription, OR'd together. Set to 0 to
- *	       use the default options, otherwise choose from the list:
+ *	options - options to apply to this subscription, OR'd together. This
+ *	          argument is not used for MQTT v3 susbcriptions. Set to 0 to use
+ *	          the default options, otherwise choose from the list:
  *	       MQTT_SUB_OPT_NO_LOCAL - with this option set, if this client
  *	                     publishes to a topic to which it is subscribed, the
  *	                     broker will not publish the message back to the