SPY-160: Queue retry op instead of redistributing it immediately.

Motivation
----------
After making the original SPY-160 changes, the ops were correctly redistributed,
but if the latch never gets counted down it gets recursively distributed and
added. Example:

	  at net.spy.memcached.protocol.TCPMemcachedNodeImpl.addOp(TCPMemcachedNodeImpl.java:344)
	  at net.spy.memcached.MemcachedConnection.addOperation(MemcachedConnection.java:1206)
	  at net.spy.memcached.MemcachedConnection.redistributeOperation(MemcachedConnection.java:994)
	  at net.spy.memcached.protocol.TCPMemcachedNodeImpl.addOp(TCPMemcachedNodeImpl.java:350)
	  at net.spy.memcached.MemcachedConnection.addOperation(MemcachedConnection.java:1206)
	  at net.spy.memcached.MemcachedConnection.redistributeOperation(MemcachedConnection.java:994)
	  at net.spy.memcached.protocol.TCPMemcachedNodeImpl.addOp(TCPMemcachedNodeImpl.java:350)
	  at net.spy.memcached.MemcachedConnection.addOperation(MemcachedConnection.java:1206)
	  at net.spy.memcached.MemcachedConnection.redistributeOperation(MemcachedConnection.java:994)

Modifications
-------------
The changeset, instead of redistributing right now, adds the operation to the retry queue which means
it will be handled eventually, but gives the IO thread a chance to run other tasks (including retreiving
auth response information).

Result
------
The operation is queued and is not blocking the IO thread.

Change-Id: I73a8e77255a54bceeb929febcadb0e555febdd67
Reviewed-on: http://review.couchbase.org/34938
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Reviewed-by: Matt Ingenthron <matt@couchbase.com>