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

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https://hg.mozilla.org/integration/gaia-central/rev/d3bba6e0bbbd
Author: Justin D'Arcangelo <justindarc@gmail.com>
Desc: Merge pull request #18039 from wilsonpage/991808

Bug 991808 - [camera] remove countdown timer sound

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https://hg.mozilla.org/integration/gaia-central/rev/d5506d7031ec
Author: Wilson Page <wilsonpage@me.com>
Desc: Bug 991808 - [camera] remove countdown timer sound
Bumping manifests a=b2g-bump