remove mccouch notification constant definitions

because mccouch is gone

Change-Id: I7374c10dee313d4c7fddf0dfedfc53289851db4b
Reviewed-on: http://review.couchbase.org/41586
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Artem Stemkovski <artem@couchbase.com>