MB-100 Add 4node sanity conf file

Change-Id: Iac9c6c4dec66b08ae9ce50daa37e2e83f55b44f3
Reviewed-on: http://review.couchbase.org/25723
Reviewed-by: Deepkaran Salooja <deepkaran.salooja@globallogic.com>
Tested-by: Deepkaran Salooja <deepkaran.salooja@globallogic.com>