Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/5b84f23f054b
Author: Mike Pennisi <mike@mikepennisi.com>
Desc: Bug 907177 - [Clock] Add integration tests

r=gaye, mcav
Bumping manifests a=b2g-bump