CBQE-2239: python implementation of start_cluster_run

make simple-test is calling a shell script that can only
run on systems that support bash. The functionality of this
script can be implemented in python to support a wider
range of operating systems

Change-Id: I9f45fcad1fbd0c34c2b9df050c7593fff6def2cb
Reviewed-on: http://review.couchbase.org/36847
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>