Bumping gaia.json for 2 gaia-1_2 revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_2/rev/2c68581569a7
Author: Alive.Kuo <alegnadise@gmail.com>
Desc: Merge pull request #12781 from alivedise/bugzilla/920890_v1.2/screenshoting

Bug 920890 - getScreenshot delays setVisible, r=vivien, a=koi+

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https://hg.mozilla.org/integration/gaia-1_2/rev/55e372299835
Author: Alive Kuo <alegnadise@gmail.com>
Desc: Bug 920890 - getScreenshot delays setVisible