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

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https://hg.mozilla.org/integration/gaia-central/rev/2fb823cf953d
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #16812 from crh0716/921391

Bug 921391 - Add DSDS support for call forwarding r=jaoo, alive

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https://hg.mozilla.org/integration/gaia-central/rev/10d1786be9c6
Author: Arthur Chen <crh0716@gmail.com>
Desc: Bug 921391 - Add DSDS support for call forwarding
Bumping manifests a=b2g-bump