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

========

https://hg.mozilla.org/integration/gaia-central/rev/1ff621b5d97f
Author: Timothy Guan-tin Chien <timdream@gmail.com>
Desc: Merge pull request #13410 from timdream/keyboard-rename-followup

Bug 935350 - Rename 'keyboard' role in homescreen, r=rudyl

========

https://hg.mozilla.org/integration/gaia-central/rev/1f26eb964f43
Author: Timothy Guan-tin Chien <timdream@gmail.com>
Desc: Bug 935350 - Rename 'keyboard' role in homescreen, +shepherd

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "6489f84d85645253962cb0197df693d63e9a42e6", 
+    "revision": "1ff621b5d97f8ded18426d49712c508402d08362", 
     "repo_path": "/integration/gaia-central"
 }