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

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https://hg.mozilla.org/integration/gaia-central/rev/b716117c0391
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #11235 from KevinGrandon/bug_872500_update_manifests

Bug 872500 - Update manifests r=baku

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https://hg.mozilla.org/integration/gaia-central/rev/3e12b71f13f5
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 872500 - Update manifests