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

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https://hg.mozilla.org/integration/gaia-central/rev/b701b2d12068
Author: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Desc: Merge pull request #16933 from 6a68/bug-980184-jshint-fxa-system-app

Bug 980184 - Fix jshint errors in FxA system app code

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https://hg.mozilla.org/integration/gaia-central/rev/74daf4ca362c
Author: Jared Hirsch <ohai@6a68.net>
Desc: Bug 980184 - Fix jshint errors in FxA system app code r=ferjm
Bumping manifests a=b2g-bump