Remove subversion from reference

Fixes gh-3766

docs/manual/src/docs/asciidoc/index.adoc

@@ -5093,7 +5093,7 @@ We've assumed here that the <<ns-config,security namespace>> is being used for c
 ==== Java EE Container Authentication
 The class `J2eePreAuthenticatedProcessingFilter` will extract the username from the `userPrincipal` property of the `HttpServletRequest`. Use of this filter would usually be combined with the use of Java EE roles as described above in <<j2ee-preauth-details>>.
 
-There is a sample application in the codebase which uses this approach, so get hold of the code from subversion and have a look at the application context file if you are interested. The code is in the `samples/preauth` directory.
+There is a sample application in the codebase which uses this approach, so get hold of the code from github and have a look at the application context file if you are interested. The code is in the `samples/preauth-xml` directory.
 
 
 [[ldap]]