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

========

https://hg.mozilla.org/integration/gaia-central/rev/d211dea69ebd
Author: Fabien Cazenave <fabien@cazenave.cc>
Desc: Merge pull request #12215 from fabi1cazenave/fdnOkButton-bug916061

 Bug 916061 - [FDN] “OK” button should be disabled when adding a new contact, r=arthurcc

========

https://hg.mozilla.org/integration/gaia-central/rev/853c6540e34f
Author: Fabien Cazenave <fabien@cazenave.cc>
Desc:  Bug 916061 - [FDN] “OK” button should be disabled when adding a new contact, r=arthurcc