Refactor named pipes connection listener completion

[JamesNK]

Two changes:

1. Move completion of the channel out of listener queues. Previously the first queue to exit would complete the channel. There is the chance another queue has just accepted a connection and attempts to put it on the channel and fails.
2. The ConnectionListenerAborted log was written inside each listener queue. That means when the transport was disposed of, it was logged 16 times. Move the log to completion, and only log if there was an error. This more closely matches sockets transport.