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

========

https://hg.mozilla.org/integration/gaia-central/rev/056dbe15b2aa
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 1033403 - [Messages] We don't stop rendering if we tap "back" too soon r=azasypkin

* moves the moment "initializeRendering" is called: in beforeEnter instead of
afterEnter.
* calls MessageManager.markThreadRead in afterEnterThread
* removes the 'done' handler in renderMessages because we don't need it now

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "remote": "", 
         "branch": ""
     }, 
-    "revision": "e21670ef83d8c9701d22267561ad4db611893811", 
+    "revision": "056dbe15b2aac2b252a119c211a85cb14165aa81", 
     "repo_path": "/integration/gaia-central"
 }