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

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https://hg.mozilla.org/integration/gaia-central/rev/6ae2e8171573
Author: Julien Wajsberg <felash@gmail.com>
Desc: Merge pull request #18646 from julienw/999553-reenable-most-disabled-unit-tests-disable-render-test

Bug 999553 - Reenable most disabled unit tests on TBPL r=jgriffin

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https://hg.mozilla.org/integration/gaia-central/rev/6350b731227b
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 999553 - Reenable most disabled unit tests on TBPL r=jgriffin
Bumping manifests a=b2g-bump