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

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https://hg.mozilla.org/integration/gaia-central/rev/318915a96a4a
Author: Florin Strugariu <bebef_1987@yahoo.com>
Desc: Merge pull request #16118 from viorelaioia/bug_970217

Bug 970217 - Unxfail test_settings_passcode.py as Bug 966476 is fixed

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https://hg.mozilla.org/integration/gaia-central/rev/7c81124ea89a
Author: Viorela Ioia <viorelaioia@gmail.com>
Desc: Bug 970217 - Unxfail test_settings_passcode.py as Bug 966476 is fixed

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "1e48642e5823e25a3b7c78853bc39606de559246", 
+    "revision": "318915a96a4ae306afe9aae33b117c3821c94c0b", 
     "repo_path": "/integration/gaia-central"
 }