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

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https://hg.mozilla.org/integration/gaia-central/rev/dde6b70ee7f6
Author: Jonathan Griffin <jgriffin@mozilla.com>
Desc: Merge pull request #12989 from jonallengriffin/unittests

Bug 928503 - Look for tests in subdirectories of 'unit', r=bkelly, a=tes...

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https://hg.mozilla.org/integration/gaia-central/rev/b0844a49b998
Author: Jonathan Griffin <jgriffin@mozilla.com>
Desc: Bug 928503 - Look for tests in subdirectories of 'unit', r=bkelly, a=test-only