MB-100: tune mcsoda throughput

Change-Id: Ie6ec7daad35acb6a8269f1e487b61a968ac69a7c
Reviewed-on: http://review.couchbase.org/25195
Reviewed-by: Pavel Paulau <pavel.paulau@gmail.com>
Tested-by: Pavel Paulau <pavel.paulau@gmail.com>