edge: dont emit empty candidates
edge: dont emit empty candidates

this fixes a regression introduced by removing the typ endOfCandidates hack in
https://github.com/webrtc/adapter/commit/e9972dd237579765c975c8364867162c6a6200bd

Basically this was emitting
  { sdpMid: ..., sdpMLineIndex: ...}
without a candidate.

webrtc/adapter,Acidburn0zzz/adapter,Acidburn0zzz/adapter,webrtc/adapter,Acidburn0zzz/adapter,jan-ivar/adapter,xdumaine/adapter,jan-ivar/adapter,xdumaine/adapter