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

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https://hg.mozilla.org/integration/gaia-central/rev/223146d81ab0
Author: Ben Kelly <bkelly@mozilla.com>
Desc: Merge pull request #12527 from wanderview/contacts-check-style

Bug 921808: Check title before setting textContent to avoid repaint. r=jmcf

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https://hg.mozilla.org/integration/gaia-central/rev/fd3985cf0be5
Author: Ben Kelly <ben@wanderview.com>
Desc: Bug 921808: Check title before setting textContent to avoid repaint