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

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https://hg.mozilla.org/integration/gaia-central/rev/d791136d48f3
Author: Mike Pennisi <mike@mikepennisi.com>
Desc: Bug 897090 - [Clock] L10n mocking is fragmented across test files r=ianliu

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https://hg.mozilla.org/integration/gaia-central/rev/0ad3e929c87a
Author: Mike Pennisi <mike@mikepennisi.com>
Desc: Bug 897089 - [Clock] Utility methods pollute global scope r=ianliu

Organizing utility methods under a single namespace increases code
readability and minimizes global namespace pollution.