Browser configuration support for Firefox 4
    
    Support of navigator.preferences that is used to access browser
    configuration was dropped in Firefox 4. This disables automatic
    configuration of user preferences in this browser that is needed
    to use Kerberos single sign-on.
    
    This patch detectes a lack of this interface and tries to
    configure the browser using new Services module introduced in
    Gecko 2 (used in Firefox 4, SeaMonkey 2.1).
    
    https://fedorahosted.org/freeipa/ticket/975