Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/fbda3cfd6cad
Author: Gabriele Svelto <gsvelto@mozilla.com>
Desc: Bug 1119831 - Fixed typos that prevented us from checking callback types correctly r=drs

========

https://hg.mozilla.org/integration/gaia-central/rev/1eca6672bd7a
Author: Gabriele Svelto <gsvelto@mozilla.com>
Desc: Bug 1035663 - Remove an icon that is unused since the last visual refresh r=drs

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "remote": "", 
         "branch": ""
     }, 
-    "revision": "ff840a2a31a2c3862d0ede6efcff46ec171385e0", 
+    "revision": "fbda3cfd6cad4b004e9df816799bd27ab4a6c46b", 
     "repo_path": "integration/gaia-central"
 }