Firefox desktop page redirects for Australis
Merge pull request #1935 from kyoshino/australis-redirects

Firefox desktop page redirects for Australis

* Bug 979527 - [australis] redirect /firefox/central to a sumo page
* Bug 979654 - [australis] redirect /firefox/security page to /firefox/trust
* Bug 979660 - [australis] redirect /firefox/technology to MDN
* Bug 979664 - [australis] redirect /firefox/performance to new Desktop Fast page
* Bug 979670 - [australis] redirect /firefox/features to new Desktop overview page