Bumping gaia.json for 3 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/5a6daeaa1735
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Merge pull request #12459 from hotzenklotz/917387_bluetooth_image

Picture in preview shows zoomed in when user opens picture received via ... r=davidflanagan

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https://hg.mozilla.org/integration/gaia-central/rev/071942033b93
Author: Tom Herold <therold@mozilla.com>
Desc: Picture in preview shows zoomed in when user opens picture received via Bluetooth.

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https://hg.mozilla.org/integration/gaia-central/rev/efc9218601b3
Author: Dave Hunt <dave.hunt@gmail.com>
Desc: Bug 922850 - Add hardware button simulation to the Gaia command line tool. r=wlachance