GUACAMOLE-393: Add session invalidation hooks to AuthenticatedUser.

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/apache/guacamole/auth/jdbc/user/RemoteAuthenticatedUser.java

@@ -136,4 +136,9 @@ public abstract class RemoteAuthenticatedUser implements AuthenticatedUser {
         return authenticationProvider;
     }
 
+    @Override
+    public void invalidate() {
+        // Nothing to invalidate
+    }
+
 }