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

========

https://hg.mozilla.org/integration/gaia-central/rev/ba7efaf080eb
Author: Gabriele Svelto <gsvelto@mozilla.com>
Desc: Bug 960280 - Generate canvases that are not displayed with the appropriate tag to reduce memory usage r=arcturus

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "cc6bfe9d45c4d818167c78c2e9b39a5a9022f95e", 
+    "revision": "ba7efaf080ebf86f5ad728cd8b02a81248b306b0", 
     "repo_path": "/integration/gaia-central"
 }