CBQE-1409: moving to inernal lbc-python client

this is the first step towards removing external sdkserver.py.
having the kv tasks internal to the work will help to provide
better control over ops and also libcouchbase based clients have
shown to be much better performing than any other smart client

Change-Id: I43752831ae5aae2dfc4add0aee83cf0b085acfde
Reviewed-on: http://review.couchbase.org/27474
Reviewed-by: Chisheng Hong <chisheng@couchbase.com>
Tested-by: Tommie McAfee <tommie@couchbase.com>