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

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https://hg.mozilla.org/integration/gaia-central/rev/aba00cfd579c
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #20664 from anefzaoui/bug-888815

Bug 888815 - [RTL] Notification stamp r=etienne

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https://hg.mozilla.org/integration/gaia-central/rev/407bb138e6ad
Author: Ahmed Nefzaoui <nefzaoui.ahmed@hotmail.com>
Desc: Bug 888815 - [RTL] Notification stamp
Bumping manifests a=b2g-bump