Bumping gaia.json for 1 gaia-1_2 revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-1_2/rev/28888c5fd0c5
Author: dwi2 <dwi2@dwi2.com>
Desc: Merge pull request #14797 from dwi2/bug937561

Bug 937561 - get both available network list and known network list, and...
(cherry picked from commit 065cba7bd8c3d8ad0ec424c2c2893b96bae6e54d)