message: Check file.tags instead of tags and calculate showAdd correctly
  Also, use angle bracket invocation for TagsWidget on quick files.
diff: updateFilter=(perform updateFilter)
  openFile=(action 'openFile')
  }}
  - {{#if (or canEdit tags)}}
  + {{#if (or this.canEdit this.file.tags)}}
  <div class='panel panel-default' local-class="TagsPanel">
  <div class='panel-heading clearfix' local-class="TagsPanel__heading">
  <h3 class='panel-title'>{{t "file_detail.tags"}}</h3>
  </div>
  <div class='panel-body'>
  - {{tags-widget
  - tags=this.file.tags
  - addTag=(action this.addTag)
  - removeTag=(action this.removeTag)
  - readOnly=(not this.canEdit)
  - showAdd=true
  - analyticsScope='Quick Files'
  - }}
  + <TagsWidget
  + @tags={{this.file.tags}}
  + @addTag={{action this.addTag}}
  + @removeTag={{action this.removeTag}}
  + @readOnly={{not this.canEdit}}
  + @showAdd={{this.canEdit}}
  + @analyticsScope='Quick Files'
  + />
  <div class="tags_clear"></div>
  </div>
  </div>
  