{UPR}:: Flow control with Rebalance-in does not satisfy condition :: max_unacked_bytes == 0

version: 3.0.0-790, centos-64 bit

1. Create 3 node cluster '10.5.2.13, 10.5.2.14, 10.5.2.15'
2. Create default bucket
3. Switch on upr flow control for the bucket
4. Send data (100K) and mutations to bucket
5. Rebalance-in 1 node (10.3.121.63) in the cluster
6. Check max_unacked_bytes == 0

Fails at Step 6

Test Run:: http://qa.hq.northscale.net/job/centos_x64--02_04--Rebalance_tests_UPR-P0/214/consoleText

Test Case:: testrunner -i /tmp/centos-64-2.0-basic-rebalance-tests-P0.ini -t rebalance.rebalancein.RebalanceInTests.rebalance_in_after_ops,nodes_in=1,nodes_init=3,replicas=1,items=100000,enable_flow_control=True,GROUP=IN

Discussed the bug with Mike, so assigning it to him

This might happen with other tests as well i.e. not related to rebalance-in.

Attaching logs.