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

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https://hg.mozilla.org/integration/gaia-central/rev/b2b97aa1abed
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #18589 from crh0716/973456

Bug 973456 - Refactor keyboard panels using AMD r=evelyn

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https://hg.mozilla.org/integration/gaia-central/rev/bb9348eb8849
Author: Arthur Chen <crh0716@gmail.com>
Desc: Bug 973456 - Refactor keyboard panels using AMD
Bumping manifests a=b2g-bump