Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/0c8884e1c043
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Revert "Bug 1023011 - (vertical-homescreen) Implement pressed state visual for App Icons"

This reverts commit 2728b437562eb0285b3f3279623d978537638bf6.
Bumping manifests a=b2g-bump