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

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https://hg.mozilla.org/integration/gaia-central/rev/aa8d8de4c55f
Author: russnicoletti <rnicoletti@mozilla.com>
Desc: Merge pull request #21552 from russnicoletti/updateSelection_unit_tests

Bug 979636 - Unit tests for video app, updateSelection r=johu

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https://hg.mozilla.org/integration/gaia-central/rev/49d0ba8c7a7d
Author: Russ Nicoletti <rnicoletti@mozilla.com>
Desc: Bug 979636 - Unit tests for video app, updateSelection
Bumping manifests a=b2g-bump