loosen restrictions introduced by bug 230606 to "subdir" to unbreak the automated tests.

modules/libpref/src/init/all.js

@@ -497,7 +497,7 @@ pref("advanced.mailftp",                    false);
 pref("image.animation_mode",                "normal");
 
 // Same-origin policy for file: URIs: 0=self, 1=samedir, 2=subdir, 3=anyfile
-pref("security.fileuri.origin_policy", 0);
+pref("security.fileuri.origin_policy", 2);
 
 // If there is ever a security firedrill that requires
 // us to block certian ports global, this is the pref