Disable qt5 dependent activity comment spec

See travis-ci/apt-package-safelist#442 for
whitelisting status of qt5 on ubuntu 12.04 or wait until 14.04 is
available on travis

spec/features/work_packages/activity_comments_spec.rb

@@ -49,7 +49,8 @@
     ng_wait
   end
 
-  it 'should alert user if navigating with unsaved form' do
+  # activate these specs once qt5 is available on travis: https://github.com/travis-ci/apt-package-whitelist/issues/442
+  xit 'should alert user if navigating with unsaved form' do
     fill_in I18n.t('js.label_add_comment_title'), with: 'Foobar'
 
     visit root_path
@@ -59,7 +60,8 @@
     expect(current_path).to eq(root_path)
   end
 
-  it 'should not alert if comment has been submitted' do
+  # activate these specs once qt5 is available on travis: https://github.com/travis-ci/apt-package-whitelist/issues/442
+  xit 'should not alert if comment has been submitted' do
     fill_in I18n.t('js.label_add_comment_title'), with: 'Foobar'
 
     click_button I18n.t('js.label_add_comment')