Issue: Robust handling server failure feature doesn't work when server_failure_limit is higher than 1

[charsyam]

@hrishimantri reported this:

1. There are 2 redis instances running on two different boxes
2. Twemproxy is installed on a client box which talks to these two boxes
3. The twemproxy configuration is as pointed in Robust hash ring failure retry mechanism #29
4. I use a Jedis Client to talk to Redis via twemproxy

Can you please go ahead and test these scenarios :
Testcase 1) Both the redis instances are up and running (twemp works fine)

Testcase 2) Stop Redis instance running on one of the box and then check if the request goes to the other slave where REDIS is up and running. If the failure_limit is set to 2 in the twemproxy conf then the node fails to be ejected. Though the Node gets ejected when the failure_limit is set to 1 and the request is then routed to the other slave.

Testcase 3) Restart the redis instance stopped in Testcase 2. The node should get restored and the requests should again be distributed randomly amongst the two slaves.

Testcase 1 and Testcase 3 work fine but Testcase 2 fails to work on failure_limit set to 2. Can you please retest this at your side ?