Remove mistakenly added Firefox attribute

manifest.json

@@ -23,11 +23,5 @@
         "scripts": ["libs/jquery.js", "backgroundPage.js"]
     },
 
-    "applications": {
-        "gecko": {
-            "id": "collateral-freedom@rsf.org"
-        }
-    },
-
     "default_locale": "en"
 }