Bumping gaia.json for 1 gaia-central revision(s)

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https://hg.mozilla.org/integration/gaia-central/rev/12233e1a8293
Author: Corey Frang <gnarf@gnarf.net>
Desc: Bug 885584 - [B2G][SMS/MMS] Thumbnails are invisible in the preview attachment with large files - r=julienw

* Sets max thumbnail generation size to 1.5 megs, which should be big enough for any mms image
* Removes a var self = this;