Bumping gaia.json for 2 gaia-1_2 revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_2/rev/5addf8ecfeb6
Author: Jose Antonio Olivera Ortega <josea.olivera@gmail.com>
Desc: Merge pull request #13784 from jaoo/927486-v1.2

(v1.2) Bug 927486 - [Settings] Modify Message settings category. r=arthurcc

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https://hg.mozilla.org/integration/gaia-1_2/rev/2f4b47248295
Author: Jose Antonio Olivera Ortega <josea.olivera@gmail.com>
Desc: (v1.2) Bug 927486 - [Settings] Modify Message settings category. r=arthurcc