MB-10481: added hostname to failover confirm dialog

Change-Id: I1d64767861e6304abb0624079cb728f5f4edcda1
Reviewed-on: http://review.couchbase.org/34726
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>