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

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https://hg.mozilla.org/integration/gaia-central/rev/f8e3e98f399a
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #11797 from crh0716/907486

Bug 907486 - Check network connectivity before using network mcc and mnc of mozMobileConnection r=evelyn a=leo+

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https://hg.mozilla.org/integration/gaia-central/rev/578a478b0d2e
Author: Arthur Chen <crh0716@gmail.com>
Desc: Bug 907486 - Check network connectivity before using network mcc and mnc of mozMobileConnection