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

========

https://hg.mozilla.org/integration/gaia-central/rev/cf15b014bb45
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #20317 from etiennesegonzac/bug-1021512-homescreen-utility-tray

Bug 1021512 - Send a touchcancel to the active app when the system starts r=21,kgrandon

========

https://hg.mozilla.org/integration/gaia-central/rev/c204da3404d6
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 1021512 - Send a touchcancel to the active app when the system starts swallowing touch events.

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "remote": "", 
         "branch": ""
     }, 
-    "revision": "3683e8cfe54e0b7c04a1b516d4a117b885e5089b", 
+    "revision": "cf15b014bb45d7fba2f239218930e65888e87968", 
     "repo_path": "/integration/gaia-central"
 }