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

========

https://hg.mozilla.org/integration/gaia-central/rev/171943c1126a
Author: Alive.Kuo <alegnadise@gmail.com>
Desc: Merge pull request #17428 from alivedise/bugzilla/982491_master/parent-app

Bug 982491 - Add parent app manifestURL if there is, r=timdream

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https://hg.mozilla.org/integration/gaia-central/rev/d13a5b8a3423
Author: Alive Kuo <alegnadise@gmail.com>
Desc: Bug 982491 - Add parent app manifestURL if there is

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "remote": "", 
         "branch": ""
     }, 
-    "revision": "a86af27e6a6db2db526d5474a68a21df3386f6b7", 
+    "revision": "171943c1126a1e874472d5e46cbe71215178c7d1", 
     "repo_path": "/integration/gaia-central"
 }