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

========

https://hg.mozilla.org/integration/gaia-central/rev/6ac9087ee6e6
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 1073157 - [System] fix wallpaper_manager.js tests with a newer mocha r=djf

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "remote": "", 
         "branch": ""
     }, 
-    "revision": "a98d7e35e673418d825e954703f1f0faa021efb2", 
+    "revision": "6ac9087ee6e6a881635f1091612d8164a8436f10", 
     "repo_path": "/integration/gaia-central"
 }