MB-9763 enable Replicas-Enable check box

... on Create Defaut Bucket page

Change-Id: Ia32c79a9844aacbc5a750b88f4ad63587ca07b99
Reviewed-on: http://review.couchbase.org/31343
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>