MB-100: rebalance test with timeout logging

Change-Id: Idc93cfaf470fd21affb201ddd0f11bf2bd55ba08
Reviewed-on: http://review.couchbase.org/24298
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>