Bug 827103 - [404] http://mozilla.org/ links to https://www.mozilla.org/en-US/firefox/17.0.1/requirements

On a computer that doesn't meet the requirements to run Firefox,
http://mozilla.org/ will lead the user to a 404 at
https://www.mozilla.org/en-US/firefox/17.0.1/requirements. Maybe it
would be better to change that link to
https://www.mozilla.org/en-US/firefox/17.0.1/system-requirements/.