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

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https://hg.mozilla.org/integration/gaia-central/rev/39737621d1f3
Author: steveck-chung <schung@mozilla.com>
Desc: Merge pull request #11187 from steveck-chung/Message-youtube-sharing

Bug 896956 - [Youtube] Share video via SMS. r=gnarf37

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https://hg.mozilla.org/integration/gaia-central/rev/25da8aea107f
Author: Steve Chung <schung@mozilla.com>
Desc: Bug 896956 - [Youtube] Share video via SMS