Add ability to override favicon in themes

[Tracy Jones]

The same way you can override logo and logo-splash - you should be able to override favicon

[Brian Tully (brian-tully)]

The favicon can be overridden by specifying the link within https://github.com/openstack/horizon/blob/master/horizon/templates/horizon/_custom_meta.html

e.g.:

<link rel="icon" href="/path/to/favicon.ico">

Here's a useful cheatsheet for favicon related info:

https://github.com/audreyr/favicon-cheat-sheet

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/195751
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=074b316cddeb3d2b4b7fb4b35e136bae6d7c7c78
Submitter: Jenkins
Branch: master

commit 074b316cddeb3d2b4b7fb4b35e136bae6d7c7c78
Author: Diana Whitten <email address hidden>
Date: Wed Jul 29 11:49:58 2015 -0700

    favicon, logo and logo-splash should allow theme overrides

    favicon, logo and logo-splash are all elements that should
    be easy to customize within a theme. By adding this path
    to the STATICFILES_DIR, this enables very granular overrides
    of any of the images located within dashboard/img, by simply
    adding an 'img' directory to your custom theme directory (or
    static directory) and providing an image with the same file
    name.

    Closes-Bug: #1448283
    Change-Id: I4feb229cac805e1b1fa3a55b5ecea1339a9fc8f9
    Co-Authored-By: Tracy Jones <email address hidden>
    Co-Authored-By: Diana Whitten <email address hidden>