Remove vestigial tabs permission

Author: jsantell

manifest.json

@@ -23,7 +23,6 @@
   ],
   "permissions": [
     "storage",
-    "tabs",
     "webNavigation",
     "http://*/*",
     "https://*/*"
@@ -38,4 +37,4 @@
       "id": "[email protected]"
     }
   }
-}
+}