Validate options of the LDAP auth plugin on installation
    
    Few of the LDAP options had any validation at all so it was
    easy to provide a bad DN template, basedn and server URL.
    
    These types of errors are now sufficient to kill the installer
    rather than letting it limp along and hope the user notices the
    failures in the output.
    
    https://fedorahosted.org/ipsilon/ticket/40
    
    Signed-off-by: Rob Crittenden <rcritten@redhat.com>
    Reviewed-by: Patrick Uiterwijk <puiterwijk@redhat.com>