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

========

https://hg.mozilla.org/integration/gaia-central/rev/81f9122221cf
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #11840 from etiennesegonzac/bug-908288-system-test-orange

Bug 908288 - fixing system app intermitent orange failures

========

https://hg.mozilla.org/integration/gaia-central/rev/e801437a7aaf
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 908288 - fixing system app intermitent orange failures r=julienw