iceTransports=relay - use vs gather

http://w3c.github.io/webrtc-pc/#rtcicetransports-enum says the following 
about the "relay" value:

	The ICE engine must only use media relay candidates such as
	candidates passing through a TURN server. This can be used to
	reduce leakage of IP addresses in certain use cases.

The "use" seems wrong. ORTC uses "gather" instead 
(http://ortc.org/wp-content/uploads/2014/08/ortc.html#rtcicegatherpolicy*) 
which does not imply ignoring host/srflx candidates a peer sent.