MB-9096: removed unused start_old_vbucket_filter_change/1 call

Change-Id: I3c6229fd39f6175f1896815c930a30e67626d2c9
Reviewed-on: http://review.couchbase.org/29322
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Artem Stemkovski <artem@couchbase.com>