Xfailed test_that_all_links_are_valid

http://qa-selenium.mv.mozilla.com:8080/view/Mozilla.com/job/mozilla.com.stage/lastCompletedBuild/testReport/tests.test_notes/TestNotes/test_that_all_links_are_valid/

Test Notes fails on stage because of bug https://bugzilla.mozilla.org/show_bug.cgi?id=939707

www.allizom.org/firefox/notes/ does not exist on STAGE and test is verifying links on the wrong page