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

========

https://hg.mozilla.org/integration/gaia-central/rev/a4a7f42eac6e
Author: Ryan VanderMeulen <ryanvm@gmail.com>
Desc: Revert "Merge pull request #12550 from zacc/bug922062"

This reverts commit caa78c37ea089a39ee3ebadd2dc2677069ccaaac, reversing
changes made to 433971682d023414a6ab2b6103708d1968ef0b0e.

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "cd9d95e4fa27f11a0b5852945757df8243a0668e", 
+    "revision": "a4a7f42eac6eb7813b097c716b264d675fceeae8", 
     "repo_path": "/integration/gaia-central"
 }