CBQE-1326: cbrestore hangs on 2.1-701 build

comment out backup.opsbeforebackup.OpsBeforeBackupTests.CreateUpdateDeleteBeforeBackup in py-4node-sanity.conf

Change-Id: If1d086e12b51ab47e4a7d1ad2dca6ef5e905ae40
Reviewed-on: http://review.couchbase.org/26713
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>