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

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https://hg.mozilla.org/integration/gaia-central/rev/d2f42e82d86f
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #12391 from crdlc/bug-919951

Bug 919951 - DateTimeFormat is no longer needed after deleting the clock in the landing page

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https://hg.mozilla.org/integration/gaia-central/rev/fabc1e9f8884
Author: crdlc <crdlc@tid.es>
Desc: Bug 919951 - DateTimeFormat is no longer needed after deleting the clock in the landing page