karma tests failing due to PDF renderer

See:

• https://gitlab.com/gitlab-org/gitlab-ce/builds/13768933
• https://gitlab.com/gitlab-org/gitlab-ce/builds/13763190

FAILED TESTS:
  PDF renderer
    successful response
      ✖ does not show loading icon
        PhantomJS 2.1.1 (Linux 0.0.0)
      Expected HTMLNode to be null.
      spec/javascripts/test_bundle.js:85618:58
      spec/javascripts/test_bundle.js:85613:13

      ✖ renders the PDF page
        PhantomJS 2.1.1 (Linux 0.0.0)
      Expected null not to be null.
      spec/javascripts/test_bundle.js:85626:63
      spec/javascripts/test_bundle.js:85613:13

    error getting file
      ✖ does not show loading icon
        PhantomJS 2.1.1 (Linux 0.0.0)
      Expected HTMLNode to be null.
      spec/javascripts/test_bundle.js:85641:58
      spec/javascripts/test_bundle.js:85636:13

      ✖ shows error message
        PhantomJS 2.1.1 (Linux 0.0.0)
      Expected '' to be 'An error occured whilst loading the file. Please try again later.'.
      spec/javascripts/test_bundle.js:85645:68
      spec/javascripts/test_bundle.js:85636:13

/cc: @jschatz1, @samrose3