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

========

https://hg.mozilla.org/integration/gaia-central/rev/f4bf404a0aa8
Author: Alive.Kuo <alegnadise@gmail.com>
Desc: Merge pull request #11531 from alivedise/bugzilla/904991/app-window-factory

Bug 904991 - App Window Factory, r=timdream

========

https://hg.mozilla.org/integration/gaia-central/rev/adceb5097431
Author: Alive Kuo <alegnadise@gmail.com>
Desc: Bug 904991 - App Window Factory