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

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https://hg.mozilla.org/integration/gaia-central/rev/4f6313014c28
Author: Gregor Wagner <anygregor@gmail.com>
Desc: Merge pull request #11648 from caiolima/close-not-test

Bug 907375 - Implementation of close() to new Notification API operationin UITest application

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https://hg.mozilla.org/integration/gaia-central/rev/448e2ef98f5e
Author: Caio Lima <ticaiolima@gmail.com>
Desc: Bug 907375 - Implementation of close() to new Notification API operation in UITest application