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

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https://hg.mozilla.org/integration/gaia-central/rev/3fdb17524a0f
Author: Timothy Guan-tin Chien <timdream@gmail.com>
Desc: Merge pull request #13749 from timdream/lockscreen-async

Bug 937630 - Remove scaling transition of lock screen to make it 60fps, r=timdream

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https://hg.mozilla.org/integration/gaia-central/rev/d31ef3573318
Author: Benoit Girard <bgirard@mozilla.com>
Desc: Bug 937630 - Remove scaling transition of lock screen to make it 60fps