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

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https://hg.mozilla.org/integration/gaia-central/rev/947ead64edf6
Author: Francisco Jordano <arcturus@ardeenelinfierno.com>
Desc: Merge pull request #13218 from crdlc/bug-927599

Bug 927599 - [Homescreen] Back out greyed out icons when offline

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https://hg.mozilla.org/integration/gaia-central/rev/5a15a8816f83
Author: crdlc <crdlc@tid.es>
Desc: Bug 927599 - [Homescreen] Back out greyed out icons when offline