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

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https://hg.mozilla.org/integration/gaia-central/rev/39b3abef5580
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #18009 from evanxd/bug-984572

Bug 984572 - JSHint fixes for js/*, js/utils and js/worker.

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https://hg.mozilla.org/integration/gaia-central/rev/3bc81bb7fb3b
Author: Evan Xd <itoyxd@gmail.com>
Desc: Bug 984572 - JSHint fixes for js/*, js/utils and js/worker.
Bumping manifests a=b2g-bump