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

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https://hg.mozilla.org/integration/gaia-central/rev/5aa4dc2b48dc
Author: Jared Hirsch <ohai@6a68.net>
Desc: Merge pull request #20517 from 6a68/bug-1017224-verification-problems

Bug 1017224: Handle firefox accounts verified signal properly

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https://hg.mozilla.org/integration/gaia-central/rev/f7d89b6a7b26
Author: Jared Hirsch <ohai@6a68.net>
Desc: Bug 1017224: Handle firefox accounts verified signal properly. r=ferjm,arthurcc

    * Also, check for updates when the settings app is unhidden.
Bumping manifests a=b2g-bump