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

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https://hg.mozilla.org/integration/gaia-central/rev/b6c2bc179775
Author: gasolin <gasolin@gmail.com>
Desc: Merge pull request #12241 from snowmantw/issue903924

Bug 903924 - [Flatfish][LockScreen] add support for large device, r=timdream

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https://hg.mozilla.org/integration/gaia-central/rev/ea5dcda9f379
Author: Greg Weng <snowmantw@gmail.com>
Desc: Bug 903924 - [Flatfish][LockScreen] add support for large device