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

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https://hg.mozilla.org/integration/gaia-central/rev/171943c1126a
Author: Alive.Kuo <alegnadise@gmail.com>
Desc: Merge pull request #17428 from alivedise/bugzilla/982491_master/parent-app

Bug 982491 - Add parent app manifestURL if there is, r=timdream

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https://hg.mozilla.org/integration/gaia-central/rev/d13a5b8a3423
Author: Alive Kuo <alegnadise@gmail.com>
Desc: Bug 982491 - Add parent app manifestURL if there is
Bumping manifests a=b2g-bump