jvb: don’t send Jetty server version

jvb/rootfs/defaults/jvb.conf

@@ -89,10 +89,12 @@ videobridge {
     http-servers {
         private {
           host = 0.0.0.0
+          send-server-version = false
         }
         public {
             host = 0.0.0.0
             port = 9090
+            send-server-version = false
         }
     }