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

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https://hg.mozilla.org/integration/gaia-central/rev/00a9ef21f108
Author: gasolin <gasolin@gmail.com>
Desc: Merge pull request #14642 from gasolin/issue-916661

Bug 916661 - Refactor Authentication Dialog in AppWindow submodule, r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/be6cefe51db9
Author: gasolin <gasolin@gmail.com>
Desc: Bug 916661 - Refactor Authentication Dialog in AppWindow submodule