remove some dead code from comaction daemon

Change-Id: Iee866eb16441824bed5a996062796cf088b7926a
Reviewed-on: http://review.couchbase.org/39547
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>