Bumping gaia.json for 2 gaia-central revision(s)

========

https://hg.mozilla.org/integration/gaia-central/rev/503c75c40029
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #12001 from KevinGrandon/bug_908953_dialer_dom

Bug 908953 - Use HTML import polyfill for dialer dom r=rik

========

https://hg.mozilla.org/integration/gaia-central/rev/c45d90bbef10
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 908953 - Use HTML import polyfill for dialer dom r=rik