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

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https://hg.mozilla.org/integration/gaia-central/rev/eb6f5e284eca
Author: Mihai Cîrlănaru <mihai@cirlanaru.com>
Desc: Merge pull request #11358 from mcirlanaru/bug_896205

Bug 896205 - [Contacts] Keep aspect ratio for image thumbnails. r=@arcturus

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https://hg.mozilla.org/integration/gaia-central/rev/deb2c1ba8a9d
Author: Mihai Cirlanaru <mihai@cirlanaru.com>
Desc: Bug 896205 - [Contacts] Keep aspect ratio for image thumbnails. r=arcturus