Bumping gaia.json for 3 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/0031431e51a3
Author: Yuren Ju <yurenju@gmail.com>
Desc: Merge pull request #13135 from yurenju/multilocale.js-2

Multilocale.js 2 r=@timdream r=@ochameau r=@Pike

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https://hg.mozilla.org/integration/gaia-central/rev/5c29f90906e5
Author: Yuren Ju <yurenju@gmail.com>
Desc: Bug 922463 - Part 2: Modified httpd extension for multilocale.js

use new build module "multilocale" to handle localization in httpd.js
extension because we no longer to push all l10n files into gaia,
meanwhile we need to handle http requests for l10n files.

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https://hg.mozilla.org/integration/gaia-central/rev/e718212ac328
Author: Yuren Ju <yurenju@gmail.com>
Desc: Bug 922463 - Part 1: rewrite build/multilocale.py in javascript