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

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https://hg.mozilla.org/integration/gaia-central/rev/b715601fc835
Author: Timothy Guan-tin Chien <timdream@gmail.com>
Desc: Merge pull request #14624 from timdream/statusbar-animation-icon

Bug 946173 - Update and remove unused and duplicate status bar icon files, r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/8c8045a17061
Author: Timothy Guan-tin Chien <timdream@gmail.com>
Desc: Bug 946173 - Update and remove unused and duplicate status bar icon files