Fix /login/ URL handling

saml/saml.go

@@ -261,7 +261,7 @@ func NewSAMLIDP(config *Config) (http.Handler, error) {
 	h := idp.Handler()
 
 	root := mux.NewRouter()
-	root.Handle(ssoURL.Path, w.Wrap(h, svc, nil))
+	root.HandlePrefix(ssoURL.Path, w.Wrap(h, svc, nil))
 	root.Handle(metadataURL.Path, h)
 	return root, nil
 }