Fixes #2312 - HTTP/2 Connection.Listener notified after first request.

Signed-off-by: Simone Bordet <simone.bordet@gmail.com>

jetty-http2/http2-client/src/main/java/org/eclipse/jetty/http2/client/HTTP2ClientConnectionFactory.java

@@ -124,15 +124,15 @@ public class HTTP2ClientConnectionFactory implements ClientConnectionFactory
             {
                 session.frames(null, this, prefaceFrame, settingsFrame);
             }
-            // Only start reading from server after we have sent the client preface,
-            // otherwise we risk to read the server preface (a SETTINGS frame) and
-            // reply to that before we have the chance to send the client preface.
-            super.onOpen();
         }
 
         @Override
         public void succeeded()
         {
+            // Only start reading from server after we have sent the client preface,
+            // otherwise we risk to read the server preface (a SETTINGS frame) and
+            // reply to that before we have the chance to send the client preface.
+            super.onOpen();
             promise.succeeded(getSession());
         }