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

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https://hg.mozilla.org/integration/gaia-central/rev/6d539d255cad
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #11470 from hotzenklotz/903521_camera_in_FF

Bug 903521 - Camera not working in gaia when run in Firefox r=kgrandon

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https://hg.mozilla.org/integration/gaia-central/rev/f2b2ca763a75
Author: Tom Herold <therold@mozilla.com>
Desc: Bug 903521 - Camera not working in gaia when run in Firefox