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

========

https://hg.mozilla.org/integration/gaia-central/rev/f88be8e2bdfe
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #14660 from etiennesegonzac/bug-949487-window-manager-insta-kill

Bug 949487 -  Harden the AppWindowManager against apps that gets insta-killed r=alive

========

https://hg.mozilla.org/integration/gaia-central/rev/cabdfa599bb7
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 949487 -  Harden the AppWindowManager against app that gets
insta-killed

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "de7d1d59e9424ae0952f773c46dad879e5cdc2ae", 
+    "revision": "f88be8e2bdfecbd76666fd486bd54fd7276f99c1", 
     "repo_path": "/integration/gaia-central"
 }