CBQE-0 :: fix validation test related failures for vbucket distribution

Change-Id: I11c090faad2b2b854ac1d1768ed905474d6efa30
Reviewed-on: http://review.couchbase.org/39585
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>