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

========

https://hg.mozilla.org/integration/gaia-central/rev/389656f845ee
Author: Diego Marcos <diego.marcos@gmail.com>
Desc: Merge pull request #15996 from dmarcos/bug958200

First working version

========

https://hg.mozilla.org/integration/gaia-central/rev/712e053e9912
Author: Diego Marcos <diego.marcos@gmail.com>
Desc: Bug 958200 - [Camera] Update Camera app to use new CameraControl API
Bumping manifests a=b2g-bump