MB-10271: combine bucket details submit buttons

necessary because chrome forgot about multiple
submit buttons in one form

Change-Id: I638ebcc8d7fc7ab5b50326cde62bdbd980a15a50
Reviewed-on: http://review.couchbase.org/33979
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>