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

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https://hg.mozilla.org/integration/gaia-central/rev/04ac921ef1ca
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #18395 from crh0716/993161

Bug 993161 - Ensure the value of 'ril.iccInfo.mbdn' is valid when starting up r=jaoo

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https://hg.mozilla.org/integration/gaia-central/rev/cdf9dfcad2a9
Author: Arthur Chen <crh0716@gmail.com>
Desc: Bug 993161 - Ensure the value of 'ril.iccInfo.mbdn' is valid when starting up

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "remote": "", 
         "branch": ""
     }, 
-    "revision": "3b348ad0a7f666f32e9851e7049ca15251e9eac8", 
+    "revision": "04ac921ef1ca9aac1ef4b4fcb0b5518c1636bef9", 
     "repo_path": "/integration/gaia-central"
 }