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

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https://hg.mozilla.org/integration/gaia-central/rev/905002bf0771
Author: steveck-chung <schung@mozilla.com>
Desc: Merge pull request #11063 from steveck-chung/bug-891785

Bug 891785 - [MMS] smil.parse doesn't work well if message.attachments is null. r=gnarf

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https://hg.mozilla.org/integration/gaia-central/rev/0a7faef8116b
Author: Steve Chung <schung@mozilla.com>
Desc: Bug 891785 - [MMS] smil.parse doesn't work well if message.attachments is null

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "9020773c7b02c00c322d0869726097eac3a47246", 
+    "revision": "905002bf0771bb51bc92d02da00ce226e5ba2cb8", 
     "repo_path": "/integration/gaia-central"
 }