[Fix] Allow assign iceServers to WebRtcPeer.prototype.server
[Fix] Allow assign iceServers to WebRtcPeer.prototype.server

Change-Id: Ic4468042019d3b981a06a4470f55a818da55f794

shelsonjava/kurento-utils-js,shelsonjava/kurento-utils-js,lcamacho/kurento-utils-js,lcamacho/kurento-utils-js