Removed EOL scanning string literal error based on testing with pyflakes

 pyflakes test_rewrites.py 
test_rewrites.py:60:124: EOL while scanning string literal
        ('/1/mobile/4.0/android/en-US/firefox-help', '/en-US/kb/popular-topics-firefox-android?as=u&utm_source=inproduct''),
                                                                                                                           ^