Remove buffering from WebRTCPeer

WebRTCPeer has a buffer that is used to hold bytes until the data channel is connected. We should remove it after the turbotunnel changes are merged (legacy/trac#33745 (moved)). What ends up happening is the reliability layer ends up retransmitting packets as they sit in the buffer, and when the data channel is finally established, all those old useless packets get sent in a mass. It's better to just drop those packets on the floor before the data channel exists.