message: fix dark theme for uploadbar
diff: @@ -90,8 +90,8 @@ module.exports = React.createClass({displayName: 'UploadBar',
  <div className="mx_UploadBar_uploadProgressOuter">
  <div className="mx_UploadBar_uploadProgressInner" style={innerProgressStyle}></div>
  </div>
  - <img className="mx_UploadBar_uploadIcon" src="img/fileicon.png" width="17" height="22"/>
  - <img className="mx_UploadBar_uploadCancel" src="img/cancel.svg" width="18" height="18"
  + <img className="mx_UploadBar_uploadIcon mx_filterFlipColor" src="img/fileicon.png" width="17" height="22"/>
  + <img className="mx_UploadBar_uploadCancel mx_filterFlipColor" src="img/cancel.svg" width="18" height="18"
  onClick={function() { ContentMessages.cancelUpload(upload.promise); }}
  />
  <div className="mx_UploadBar_uploadBytes">
  