Bumping gaia.json for 1 gaia-central revision(s)

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https://hg.mozilla.org/integration/gaia-central/rev/acc045b4a6b5
Author: Arthur Chen <crh0716@gmail.com>
Desc: Revert "Bug 891743 - Add voice privacy mode for CDMA"

This reverts commit c5cd9baaef9aef54a724e264005f56d98c93ec0e.

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "4296bbf526e4ed8d0ae443f20947bd2d7189aa0e", 
+    "revision": "acc045b4a6b524013d07f4187cb2498043f32c5b", 
     "repo_path": "/integration/gaia-central"
 }