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

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https://hg.mozilla.org/integration/gaia-central/rev/840927fb8832
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #12568 from crdlc/bug-921377

Bug 921377 - E.me Collection name translation

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https://hg.mozilla.org/integration/gaia-central/rev/8d286f14d6d5
Author: crdlc <crdlc@tid.es>
Desc: Bug 921377 - E.me Collection name translation