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

========

https://hg.mozilla.org/integration/gaia-central/rev/13abe6c60a2b
Author: Sam Joch <samuel@guiora.com>
Desc: Merge pull request #10398 from pivanov/bug-865155

Bug 865155 - Email divider lines are incorrect. They should have a 15 pixel gap at both ends to match system. | Follow up patch r=@samjoch

========

https://hg.mozilla.org/integration/gaia-central/rev/8d0be4b49fab
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Bug 865155 - Email divider lines are incorrect. They should have a 15 pixel gap at both ends to match system. | Follow up patch