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

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https://hg.mozilla.org/integration/gaia-central/rev/2dc51014b8ae
Author: gasolin <gasolin@gmail.com>
Desc: Merge pull request #12689 from gasolin/issue-917359

Bug 917359 - Remember my choice is exposed for the getUserMedia dialog, ..., r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/f8f9f045b8e2
Author: gasolin <gasolin@gmail.com>
Desc: Bug 917359 - Remember my choice is exposed for the getUserMedia dialog, but shouldn't be