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>

Author: daschl

src/main/java/net/spy/memcached/MemcachedConnection.java

@@ -1418,4 +1418,14 @@ private void logRunException(final Exception e) {
   public boolean isShutDown() {
     return shutDown;
   }
+
+  /**
+   * Add a operation to the retry queue.
+   *
+   * @param op the operation to retry.
+   */
+  public void retryOperation(Operation op) {
+    retryOps.add(op);
+  }
+
 }

src/main/java/net/spy/memcached/protocol/TCPMemcachedNodeImpl.java

@@ -347,7 +347,7 @@ public final void addOp(Operation op) {
           getLogger().debug("Redistributing Operation " + op + " because auth "
             + "latch taken longer than " + authWaitTime + " milliseconds to "
             + "complete on node " + getSocketAddress());
-          connection.redistributeOperation(op);
+          connection.retryOperation(op);
         } else {
           op.cancel();
           getLogger().warn("Operation canceled because authentication "