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

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https://hg.mozilla.org/integration/gaia-central/rev/f07673802f2d
Author: Jose Antonio Olivera Ortega <josea.olivera@gmail.com>
Desc: Merge pull request #13504 from jaoo/927486

Bug 927486 - [Settings] Modify Message settings category. r=arthurcc

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https://hg.mozilla.org/integration/gaia-central/rev/7be0e40410a4
Author: Jose Antonio Olivera Ortega <josea.olivera@gmail.com>
Desc: Bug 927486 - [Settings] Modify Message settings category