MB-21684: Dump the connection object for invalid notifications
MB-21684: Dump the connection object for invalid notifications

Add a full JSON dump of the connection object if an engine
calls notify_io_complete on a cookie which isn't bound to
a worker thread (which it should be).

This may be used to figure out where the cookie came from
and why we're seeing such problems.

Change-Id: Ieee0c0121a8ca5ffdd0a43f7f3a4bd88deeeddfc
Reviewed-on: http://review.couchbase.org/90431
Reviewed-by: Daniel Owen <b3fc0e1a51f252986e60be7da121b74d3ac6845f@couchbase.com>
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Dave Rigby <a09264da4832c7ff1d3bf1608a19f4b870f93750@couchbase.com>

daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine