SAML2: Update test hostname to be less odd
    
    Rob pointed out to me that "sp2-example.com" is a slightly strange
    hostname, and that "sp2-test.example.com" would be more sane.
    
    Signed-off-by: Patrick Uiterwijk <puiterwijk@redhat.com>
    Reviewed-by: Pierre-Yves Chibon <pingou@pingoured.fr>
    Reviewed-by: Rob Crittenden <rcritten@redhat.com>