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

========

https://hg.mozilla.org/integration/gaia-central/rev/52650e68be56
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #10955 from masap/20130713

Bug 893299 - Erase CSS error message r=arthurcc

========

https://hg.mozilla.org/integration/gaia-central/rev/f9815731edaf
Author: masap <masashi.honma@gmail.com>
Desc: Bug 893299 - Erase CSS error message