Remove unused

Author: Katsute

src/main/java/com/kttdevelopment/simplehttpserver/HttpSessionImpl.java

@@ -116,7 +116,7 @@ public final HttpSessionHandler getHttpSessionHandler(){
             }
 
             @Override
-            public HttpSession getHttpSession(final HttpExchange exchange){
+            public final HttpSession getHttpSession(final HttpExchange exchange){
                 return sessionHandler.getSession(exchange);
             }