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

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https://hg.mozilla.org/integration/gaia-central/rev/366bc52b7681
Author: Jared Hirsch <ohai@6a68.net>
Desc: Merge pull request #18384 from 6a68/revert-bug-987418

Revert "Bug 987418 - Update copy in fxa system app r=ferjm"

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https://hg.mozilla.org/integration/gaia-central/rev/1e89057ee303
Author: Jared Hirsch <ohai@6a68.net>
Desc: Revert "Bug 987418 - Update copy in fxa system app r=ferjm"

This reverts commit 01f9a841050c5f66f511f34804e298b3ec1dd30d.
Bumping manifests a=b2g-bump