Add V3 API Test to get the VNC console of server

This patch adds V3 API Test to get the VNC console of server

Change-Id: I120163d0821eb7d8b2d62000be7cdd991925c341
diff --git a/etc/tempest.conf.sample b/etc/tempest.conf.sample
index 95a4884..0a78528 100644
--- a/etc/tempest.conf.sample
+++ b/etc/tempest.conf.sample
@@ -359,6 +359,10 @@
 # iSCSI volumes (boolean value)
 #block_migrate_cinder_iscsi=false
 
+# Enable VNC console. This configuration value should be same
+# as [nova.vnc]->vnc_enabled in nova.conf (boolean value)
+#vnc_console=false
+
 
 [dashboard]