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

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https://hg.mozilla.org/integration/gaia-central/rev/84f6598057e1
Author: Carsten Book <tomcat@mozilla.com>
Desc: Merge pull request #31544 from anu7495/fadefix

Bug 1004036 - clearing of notifications fade during drag. r=dietrich r=apastor

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https://hg.mozilla.org/integration/gaia-central/rev/17b23fdc21d0
Author: anu7495 <anubhav.worklinux@gmail.com>
Desc: Bug 1004036 - clearing of notifications fade during drag r=dietrich

b2g/config/gaia.json

@@ -1,9 +1,9 @@
 {
     "git": {
-        "git_revision": "839875ab81dd04bc6c9fa9f915469b0c708285b5", 
+        "git_revision": "9d99f5d807444040209b9786032b7a53881f827e", 
         "remote": "https://git.mozilla.org/releases/gaia.git", 
         "branch": ""
     }, 
-    "revision": "280c4cb090edf40f7af6e1a07229137110dad29a", 
+    "revision": "84f6598057e184064fcb3ba7f47c18add156ce37", 
     "repo_path": "integration/gaia-central"
 }