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

========

https://hg.mozilla.org/integration/gaia-central/rev/f7a78194ae8e
Author: Rick Waldron <waldron.rick@gmail.com>
Desc: Bug 951339 - [Messages][Drafts] Existing thread drafts not properly populated when a new message is sent to that same recipient r=julienw

https://bugzilla.mozilla.org/show_bug.cgi?id=951339
Signed-off-by: Rick Waldron <waldron.rick@gmail.com>

========

https://hg.mozilla.org/integration/gaia-central/rev/25b217bf4c6f
Author: Rick Waldron <waldron.rick@gmail.com>
Desc: Bug 952225 - [Messages][Drafts] Support subject line in message drafts r=julienw

https://bugzilla.mozilla.org/show_bug.cgi?id=952225
Signed-off-by: Rick Waldron <waldron.rick@gmail.com>

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "fd425823b0bc4b8ad0f102b0b25b77f61bb9e8ae", 
+    "revision": "f7a78194ae8eddcc20af610abed89bac359067d2", 
     "repo_path": "/integration/gaia-central"
 }