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/49b2c7c3c5c8
Author: gasolin <gasolin@gmail.com>
Desc: fix Bug 921404 uplift

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https://hg.mozilla.org/integration/gaia-1_2/rev/ffb2efcc0daa
Author: gasolin <gasolin@gmail.com>
Desc: Bug 921404 - [Flatfish][Lockscreen] screen clock is too small on tablet