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

========

https://hg.mozilla.org/integration/gaia-central/rev/d9f759cc1093
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #11806 from crdlc/bug-896873

Bug 896873 - [B2G][Helix][Icon]After upgrade the OS, all of the icons are grey

========

https://hg.mozilla.org/integration/gaia-central/rev/1fa989916b01
Author: crdlc <crdlc@tid.es>
Desc: Bug 896873 - [B2G][Helix][Icon]After upgrade the OS, all of the icons are grey