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

========

https://hg.mozilla.org/integration/gaia-central/rev/557d2a3432f0
Author: Gregor Wagner <anygregor@gmail.com>
Desc: Merge pull request #18901 from ckerschb/cspTestContainerFix

Bug 858787 - Loading css for test-container from external file. r=fabrice

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https://hg.mozilla.org/integration/gaia-central/rev/35723984b298
Author: Christoph Kerschbaumer <mozilla@christophkerschbaumer.com>
Desc: Flipping pref csp.speccompliant causes tests to fail on the B2G Emulator,
because test-container/index.html uses an inline-style which is blocked by CSP.
Rewrite of the *.html file to load the css/style information from an external file
CSP does not block it.

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "remote": "", 
         "branch": ""
     }, 
-    "revision": "51e7f035fcf9f66af1993922da347ff77629a88c", 
+    "revision": "557d2a3432f051075e8abf16adb649ad6c08ce00", 
     "repo_path": "/integration/gaia-central"
 }