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

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https://hg.mozilla.org/integration/gaia-central/rev/43e19056e5db
Author: Jim Porter <jporter@mozilla.com>
Desc: Merge pull request #21191 from jimporter/ringtones-create-window-stack

Bug 1030954 - [ringtones][window management] create ringtone screen does...

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https://hg.mozilla.org/integration/gaia-central/rev/879e38352adb
Author: Jim Porter <jporter@mozilla.com>
Desc: Bug 1030954 - [ringtones][window management] create ringtone screen doesn't appear on subsequent tries

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "remote": "", 
         "branch": ""
     }, 
-    "revision": "eafe46cf2934f14a6a7ee3dfb88b347c7e918f13", 
+    "revision": "43e19056e5dbb4513e4f84a86fc84dadf14a4097", 
     "repo_path": "/integration/gaia-central"
 }