Remove subscriptionReference check in PullMessageResponse

The ONVIF Core Spec is a bit vague but from what I can understand an Event message
that comes back from a PullMessage command does
not need to include a subscriptionReference (and HikVision don't send it)

If the library used the other events mechanism, where
the NVT sends a Notity message to this llibrary then we would check the subscriptionReference.
But this library does not support that method of events.

Thanks to
Michiel Mooring @Gielert who reported the issue
Nick Whyte @nickw444 - who has used this in his fork

lib/events.js

@@ -201,15 +201,12 @@ module.exports = function(Cam) {
 							data.notificationMessage = [data.notificationMessage];
 						}
 						data.notificationMessage.forEach(function(message) {
-							// pull-point address check
-							if (message.subscriptionReference.address === this.events.subscription.subscriptionReference.address.href) {
-								/**
-								 * Indicates message from device.
-								 * @event Cam#event
-								 * @type {Cam~NotificationMessage}
-								 */
-								this.emit('event', message);
-							}
+							/**
+							 * Indicates message from device.
+							 * @event Cam#event
+							 * @type {Cam~NotificationMessage}
+							 */
+							this.emit('event', message);
 						}.bind(this));
 					}
 					this.events.terminationTime = _terminationTime(data);