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

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https://hg.mozilla.org/integration/gaia-central/rev/fdaf66a0aaa7
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #26182 from KevinGrandon/bug_1081731_locales_follow_up

Bug 1081731 - Locales follow-up, use brandShortName

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https://hg.mozilla.org/integration/gaia-central/rev/1663e097e0f0
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1081731 - Follow-up, use brandShortName and split private browsing strings r=flod
Bumping manifests a=b2g-bump