remove unused control from Internal Settings UI

Change-Id: I29952665d30378cf16eb6af5416ce9e1d3b13b10
Reviewed-on: http://review.couchbase.org/44257
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>