Fix Bug 1105664 Add a1 to hello/start redirect

https://bugzilla.mozilla.org/show_bug.cgi?id=1105664

@jgmize sorry Josh, we also need to redirect a1 versions.

https://www.mozilla.org/en-US/firefox/36.0a2/hello/start - redirects okay
https://www.mozilla.org/en-US/firefox/36.0a1/hello/start - 404 (this PR will include it)