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

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https://hg.mozilla.org/integration/gaia-central/rev/5ac18f35181f
Author: Jonathan Griffin <jgriffin@mozilla.com>
Desc: Merge pull request #11149 from jonallengriffin/suggestion

Bug 897558 - Disable suggestion_bar_test.js for frequent TBPL orange, a=...

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https://hg.mozilla.org/integration/gaia-central/rev/c2952d65ae55
Author: Jonathan Griffin <jgriffin@mozilla.com>
Desc: Bug 897558 - Disable suggestion_bar_test.js for frequent TBPL orange, a=test-only

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "40e122f61752670e9fe4a5f3f3849a36d9045ccc", 
+    "revision": "5ac18f35181f06864be6603b114f3763375021c2", 
     "repo_path": "/integration/gaia-central"
 }