fix saml/login location for Kerberos SSO

According to nextcloud/user_saml#118 and my own experiments the protected path needs to change.
I'm unsure when this changed, but with the change Kerberos SSO works as expected.

admin_manual/configuration_server/sso_configuration.rst

@@ -51,7 +51,7 @@ would protect the login route:
 
 .. code-block:: apache
 
-    <Location "/index.php/login">
+    <Location "/index.php/apps/user_saml/saml/login">
     	AuthType Kerberos
     	AuthName "Kerberos Login"
     	KrbServiceName HTTP
@@ -66,4 +66,4 @@ would protect the login route:
 
 
 .. warning:: If this authentication approach is used clients do require an application specific password for authentication.
-             A better integration into our desktop and mobile clients is considered for the future though.
+             A better integration into our desktop and mobile clients is considered for the future though.