message: comment out `visibility:hidden` div as it seems unfinished
  and refers to undefined method `this._onJoinGroupClick`
diff: @@ -124,7 +124,7 @@ export default withMatrixClient(React.createClass({
  ) }
  </div>
  </div>
  - <div className="mx_MyGroups_joinBox mx_MyGroups_headerCard">
  + {/*<div className="mx_MyGroups_joinBox mx_MyGroups_headerCard">
  <AccessibleButton className='mx_MyGroups_headerCard_button' onClick={this._onJoinGroupClick}>
  <TintableSvg src="img/icons-create-room.svg" width="50" height="50" />
  </AccessibleButton>
  @@ -140,7 +140,7 @@ export default withMatrixClient(React.createClass({
  { 'i': (sub) => <i>{ sub }</i> })
  }
  </div>
  - </div>
  + </div>*/}
  </div>
  <div className="mx_MyGroups_content">
  { contentHeader }
  