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

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https://hg.mozilla.org/integration/gaia-central/rev/eb6694cbb975
Author: Bob Silverberg <bob.silverberg@gmail.com>
Desc: Merge pull request #14012 from zacc/bug_937336_messages

Bug 937336 - Python remove explicit frame switching from Messages app ob...

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https://hg.mozilla.org/integration/gaia-central/rev/829f3947e4b7
Author: Zac Campbell <zcampbell@mozilla.com>
Desc: Bug 937336 - Python remove explicit frame switching from Messages app object

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "581a7d1786bbb5e8bd472451713568aaff2486b3", 
+    "revision": "eb6694cbb9750dc81c48842205a3740306ddfcd5", 
     "repo_path": "/integration/gaia-central"
 }