setWait for a value to not be equal to something

this enables an attribute to be provided to Server.setWait and it will
wait until it is not equal to the associated value.  example:

    server.setWait(
      { status:'ACTIVE', accessIPv4:{$ne:''} },
      { interval:2000 },
      function(err, server) {
        // We now know that the server is active and that
        // the accessIPv4 property has been populated.
      }
    );