Get rid of the pubnub warning message and set the default origin to "pub...

<h2>ABSTRACT:</h2>

Get rid of the pubnub warning message and set the default origin to "pubsub.pubnub.com".
See also: <https://help.pubnub.com/entries/21403311-How-Do-I-Use-a-Custom-Origin->.

<h2>REVIEWER(S):</h2>

@larsxschneider 

<h2>TESTING:</h2>

Manual testing.

Setting the origin to "pubsub.pubnub.com" is suggested by pubnub support. Besides, there is no setOrigin method to call. The resetOrigin method does not help because it just sets the origin to back to defaultOrigin.