Fix "Open Console" issue on network topology

Now when user click the link "Open Console" on the instance balloon of
network topology panel, two windows will be opened. This patch fixes
that.

Closes-Bug: #1702189

Change-Id: I7459e990cac4c6df79c4972e2d5b5b4dee9eb428

openstack_dashboard/static/js/horizon.flatnetworktopology.js

@@ -102,6 +102,7 @@ horizon.flat_network_topology = {
       })
       .on('click', 'a.vnc_window', function(e) {
         e.preventDefault();
+        e.stopImmediatePropagation();
         var vnc_window = window.open($(this).attr('href'), vnc_window, 'width=760,height=560');
         self.delete_balloon();
       })