CBQE-0: simplify default testcfg.py

making testcfg.py more generic for simpliest setup

Change-Id: I38941aec654285617e19f9e6e8e895c0eec7be81
Reviewed-on: http://review.couchbase.org/37049
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Aruna Piravi <aruna@couchbase.com>