CBST-10: fix for multi-bucket loading

There is currently a bug loading to multiple buckets, where the sdk is reusing the connection for the first bucket and applies all of the workloads there instead of making a new connection to all the specified buckets.

Change-Id: I3ae3e73aecb1916f96cea92a04411c2260811fa8
Reviewed-on: http://review.couchbase.org/29501
Reviewed-by: Thuan Nguyen <soccon@gmail.com>
Tested-by: Tommie McAfee <tommie@couchbase.com>