MB-100: Toybuild to point to kvshard6

- Static allocation:
    - 4 readers + 2 writers per bucket
- MRW34

Change-Id: I16bdd4943a19c91a1e21eb9b3525849fc87615bb
Reviewed-on: http://review.couchbase.org/26271
Reviewed-by: abhinav dangeti <abhinav.dangeti@gmail.com>
Tested-by: abhinav dangeti <abhinav.dangeti@gmail.com>