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

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https://hg.mozilla.org/integration/gaia-central/rev/4934835d11f6
Author: Gregor Wagner <anygregor@gmail.com>
Desc: Merge pull request #17784 from gregorwagner/bug989785

Bug 989785 - Disable failing test. r=me

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https://hg.mozilla.org/integration/gaia-central/rev/c2287557f2e1
Author: Gregor Wagner <anygregor@gmail.com>
Desc: Bug 989785 - Disable failing test. r=me
Bumping manifests a=b2g-bump