Stats call can hang

The Stats call in gocb can sometimes hang. For instance if there are 3 nodes, and 1 is running very slowly then the following can happen: node1 response returns, node2 response returns, node3 response times out. In this scenario as node1 and node2 responses have returned the Cancel() call on the multiop returns false. After this gocb waits for the signal, but it waits indefinitely as the timeout has removed the node3 request from the queue so that request never completes to cause the signal to be fired.