CBQE-1161: Fix incremental_rebalance_in_out_with_max_buckets_number

no we have limitation in 10 buckets

Change-Id: Ib9ca73cc2f325b4b5c247301dc915b4e89dccbe6
Reviewed-on: http://review.couchbase.org/25539
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>