handleDial published to the calls.track subject keyed by channel.id, while
trackCall registers the client stream keyed by the ref CreateCall returned.
The two identifiers never match, so every dial event was dropped and the
statusStream from Calls.createCall stayed empty for the life of the call.
Resolve the CALL_REF channel variable, which the originate in runCallManager
and the local-ctx-common dialplan both set, and publish under that. Channels
with no call ref have no TrackCall request waiting on them, so the event is
skipped instead of published under an id nothing can match.
Refs #883
