CBQE-946: optmizations in upgrade tests

import optimization
remove op_types=data,bucket that are useless
code cleanup in verification()
rem _verify_upgrade_rebalance_in_out that is the same as verification() method
_load_data_all_buckets is depricated

Change-Id: Ib325947ac646e8bf7cb90368ecc812e905adbc12
Reviewed-on: http://review.couchbase.org/23631
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>