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

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https://hg.mozilla.org/integration/gaia-central/rev/4ee9d0390649
Author: Alive.Kuo <alegnadise@gmail.com>
Desc: Merge pull request #14632 from alivedise/bugzilla/948596_v2/activity-window-size-copy

Bug 948596 - fullscreen state of activity window, r=timdream

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https://hg.mozilla.org/integration/gaia-central/rev/767ecb92b6e8
Author: Alive Kuo <alegnadise@gmail.com>
Desc: Bug 948596 - fullscreen state of activity window