MB-11425: 'Metadata Purge Interval' is the header

Change-Id: Ic7cd21610fc255de5a19710fe5a506262d0756ce
Reviewed-on: http://review.couchbase.org/38303
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
MB-11357: display corresponding status message

Change-Id: I45544585fd2d043e16a10b59f9880227cb0dc1f2
Reviewed-on: http://review.couchbase.org/38305
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>