message: Correct confirm prompt for disinvite
  It should be 'disinvite' not 'kick', and probably doesn't really
  need a reason.
diff: @@ -218,11 +218,13 @@ module.exports = WithMatrixClient(React.createClass({
  },
  onKick: function() {
  + const membership = this.props.member.membership;
  + const kickLabel = membership === "invite" ? "Disinvite" : "Kick";
  const ConfirmUserActionDialog = sdk.getComponent("dialogs.ConfirmUserActionDialog");
  Modal.createDialog(ConfirmUserActionDialog, {
  member: this.props.member,
  - action: 'Kick',
  - askReason: true,
  + action: kickLabel,
  + askReason: membership == "join",
  danger: true,
  onFinished: (proceed, reason) => {
  if (!proceed) return;
  