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

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https://hg.mozilla.org/integration/gaia-central/rev/090c8de8ca1c
Author: steveck-chung <schung@mozilla.com>
Desc: Merge pull request #21849 from steveck-chung/bug-1015390

Bug 1015390 - [SMS] Implement new startup loading events r=julienw

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https://hg.mozilla.org/integration/gaia-central/rev/01d72446b272
Author: Steve Chung <schung@mozilla.com>
Desc: Bug 1015390 - [SMS] Implement new startup loading events

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "remote": "", 
         "branch": ""
     }, 
-    "revision": "dd035f2129944c8df269952ceb08f9585623d605", 
+    "revision": "090c8de8ca1cfa90d3640cbab36f4a2e5a1996cb", 
     "repo_path": "/integration/gaia-central"
 }