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

========

https://hg.mozilla.org/integration/gaia-central/rev/9f3b6b772b7b
Author: Julien Wajsberg <felash@gmail.com>
Desc: Revert "Merge pull request #21162 from yurenju/callscreen"

This reverts commit 061e9b84a9742fa9ad0519b7b98f1b50fc212be8, reversing
changes made to 34df8238f7367ac99b6897a073b9cc2f82f5371a.

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "remote": "", 
         "branch": ""
     }, 
-    "revision": "889f661704b97eb1f082f229fc02417ae7c1a30f", 
+    "revision": "9f3b6b772b7b8b45634f9911c873f59a8036e9a9", 
     "repo_path": "/integration/gaia-central"
 }