MB-10840 Remove vbucket from indexes before deleting it.

Change-Id: I0e7c394d3287da30cabbd0be5decd007d61a3231
Reviewed-on: http://review.couchbase.org/35617
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>