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

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https://hg.mozilla.org/integration/gaia-central/rev/6c65a5707548
Author: Hubert Figuière <hub@figuiere.net>
Desc: Merge pull request #23736 from hfiguiere/bug947816-metadata-unit-test

Bug 947816 - metadata unit test r=squib

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https://hg.mozilla.org/integration/gaia-central/rev/3a367e41fd8e
Author: Hubert Figuière <hub@figuiere.net>
Desc: Bug 947816 - Part 2: Add metadata test for VorbisComment (.ogg) id3v1 and AAC (.m4a)
Bumping manifests a=b2g-bump