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

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https://hg.mozilla.org/integration/gaia-central/rev/d9f759cc1093
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #11806 from crdlc/bug-896873

Bug 896873 - [B2G][Helix][Icon]After upgrade the OS, all of the icons are grey

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https://hg.mozilla.org/integration/gaia-central/rev/1fa989916b01
Author: crdlc <crdlc@tid.es>
Desc: Bug 896873 - [B2G][Helix][Icon]After upgrade the OS, all of the icons are grey

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "e4e28ac6f7a13ee205cdcdede3ce13aff9227997", 
+    "revision": "d9f759cc10938a3caa252e96420531bbb6d6cab3", 
     "repo_path": "/integration/gaia-central"
 }