Bumping gaia.json for 1 gaia-central revision(s)

========

https://hg.mozilla.org/integration/gaia-central/rev/4ef712b02d79
Author: Anthony Ricaud <anthony@ricaud.me>
Desc: Revert "Bug 914886 - [Settings] Use aria-disabled instead of disabled class"

This reverts commit ab7d53c48864e04332df1b1d396457d1d57397dd because it breaks the linter

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "24398ddc694ba8d56cc4c0bd2baaf50337598722", 
+    "revision": "4ef712b02d79d888bfe2d89db05e08dff9b32640", 
     "repo_path": "/integration/gaia-central"
 }