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

========

https://hg.mozilla.org/integration/gaia-2_1/rev/f2a4bcf6f11a
Author: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Desc: Revert "Bug 1062527 - [Homescreen] Unable to launch apps after changing the date to a previous one"

This reverts commit 98e6d28c55e699a153fdcbd0b5f2ae6cb188bb9e.
Bumping manifests a=b2g-bump