do not validate bucket_full_access roles during the Spock upgrade
do not validate bucket_full_access roles during the Spock upgrade

since the definition for this role is not among 4.5 definitions,
the upgrade fails on validation

Change-Id: I3f0c88709d3ea9c5efc4571234d900555413a064
Reviewed-on: http://review.couchbase.org/77589
Tested-by: Artem Stemkovski <15a0730a27c69f62ab86f2b6c639fca202166c02@couchbase.com>
Reviewed-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>

membase/ns_server,membase/ns_server,membase/ns_server,membase/ns_server,membase/ns_server,membase/ns_server