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

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https://hg.mozilla.org/integration/gaia-central/rev/7560c086766c
Author: Alive.Kuo <alegnadise@gmail.com>
Desc: Merge pull request #10557 from alivedise/bugzilla/859167_master

Bug 859167 - Prevent touch events on homescreen during app to app transi...r=timdream

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https://hg.mozilla.org/integration/gaia-central/rev/258dcbb8417f
Author: Alive Kuo <alegnadise@gmail.com>
Desc: Bug 859167 - Prevent touch events on homescreen during app to app transition