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

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https://hg.mozilla.org/integration/gaia-central/rev/d074ca29d44b
Author: Diego Marcos <diego.marcos@gmail.com>
Desc: Merge pull request #15220 from dmarcos/bug958555

Bug 958555 - Accesing the Camera app from the Message app using marionet...

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https://hg.mozilla.org/integration/gaia-central/rev/3f6cd1a5d2d9
Author: Diego Marcos <diego.marcos@gmail.com>
Desc: Bug 958555 - Accesing the Camera app from the Message app using marionette, causes the Camera app to become unresponsive