MB-100 Remove useless function.

It didn't do what it stated in it's name. And what it actually did is
already done by ensure_rep_db_exists called from changes_feed_loop.

Change-Id: Ie7c146427ab78cc6607ad30c48e9cffe372fae90
Reviewed-on: http://review.couchbase.org/28163
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>