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

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https://hg.mozilla.org/integration/gaia-central/rev/723aae7eb1cd
Author: vingtetun <21@vingtetun.org>
Desc: Merge pull request #16309 from vingtetun/bug972365-v3

Bug 972365 - event.preventDefault() is called unexpectedly in apps/syste...

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https://hg.mozilla.org/integration/gaia-central/rev/0d76f8810d19
Author: Vivien Nicolas <21@vingtetun.org>
Desc: Bug 972365 - event.preventDefault() is called unexpectedly in apps/system/js/browser_context_menu.js. r=kgrandon
Bumping manifests a=b2g-bump