ReplicatedConsistentHash.isKeyLocalToNode(node, key) should return false if the node is not a member yet

isKeyLocalToNode currently returns true all the time. Failing to implement isKeyLocalToNode properly makes it impossible to detect if the key is not yet available locally (because state transfer is still in progress) and should be fetched remotely before proceeding with a conditional command. This is a prerequisite for ISPN-2757.