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

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https://hg.mozilla.org/integration/gaia-central/rev/cf970b98300e
Author: John Hu <johu@mozilla.com>
Desc: Merge pull request #14913 from gurumukhi/patch-2

Bug 892950 - error-network message can use better English, r=johu

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https://hg.mozilla.org/integration/gaia-central/rev/2282b6b8ac26
Author: Ram Dayal Vaishnav <vaishnav.rd@gmail.com>
Desc: Bug 892950 - error-network message can use better English