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

========

https://hg.mozilla.org/integration/gaia-central/rev/2bffd56ad34a
Author: Carsten Book -Tomcat- <cbook@mozilla.com>
Desc: Revert "Bug 937630 - All you need is ... smooth unlock transition" for bustage in Gaia Unit Tests

This reverts commit 68fc2b25ce4648ca70be8efc589b81cb0bab4465.