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

========

https://hg.mozilla.org/integration/gaia-central/rev/3b555972f151
Author: b2gautomation <jonallengriffin@gmail.com>
Desc: Bug 907941 - gaia-ui-tests-pushbot (see bug)

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "1f00bab62f430f0141d91e708fcf5720fb426dc6", 
+    "revision": "3b555972f1517462075aa08f68a648559ebfe4ff", 
     "repo_path": "/integration/gaia-central"
 }