CBQE-1039: fix not my vbucket errors

do reconfig vbuckets when memcachedError7 thrown.
requires latest change from sdkserver.py as well:
https://github.com/tahmmee/couchbase-python-client/commit/21180807d8e08e4f3acdb999a5805664763fb9a1

Change-Id: I3349a93050eeec33484208b9e407f3532b11bb87
Reviewed-on: http://review.couchbase.org/24567
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Tommie McAfee <tommie@couchbase.com>