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

========

https://hg.mozilla.org/integration/gaia-central/rev/864dfd0e6f53
Author: Arnau <arnau@arnaumarch.com>
Desc: Merge pull request #17451 from rnowm/986512

Bug 986512 - Switches [BB] remove transition

========

https://hg.mozilla.org/integration/gaia-central/rev/7bc73c337dc8
Author: rnowm <arnau@arnaumarch.com>
Desc: Bug 986512 - Switches [BB] remove transition

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "branch": "", 
         "revision": ""
     }, 
-    "revision": "9bb30b77853f07d5d31222d667cb3bb535067d40", 
+    "revision": "864dfd0e6f53b4e0078826941c1206adaa0944c6", 
     "repo_path": "/integration/gaia-central"
 }