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

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https://hg.mozilla.org/integration/gaia-central/rev/ca4ff544cabf
Author: Ben Francis <ben@tola.me.uk>
Desc: Merge pull request #10508 from daleharvey/817829

Bug 817829 - Remove misplaced background highlight on awesomescreen r=benfrancis

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https://hg.mozilla.org/integration/gaia-central/rev/fc62288e6d0f
Author: Dale Harvey <dale@arandomurl.com>
Desc: Bug 817829 - Remove misplaced background highlight on awesomescreen