edge: fix bundle issue
edge: fix bundle issue

the code did not handle this rather common case:
```
pc.addStream(stream);
pc.setRemoteDescription(type=offer, sdp: bundle-av)
```
and did not dispose the second transport leading to
a weird connection failure.

webrtc/adapter,xdumaine/adapter,Acidburn0zzz/adapter,xdumaine/adapter,Acidburn0zzz/adapter,webrtc/adapter,Acidburn0zzz/adapter