Always sleep while sending boot command
Always sleep while sending boot command

Keyboard input buffer overruns are not limited to Windows batch files.
The phenomenon has been reproducibly observed on a Linux host as well.
This prevents the distro installer from coming up with error messages
that are difficult to diagnose for users. Therefore, we enable the
delay unconditionally.

Change-Id: I2ad8f437ec1ebadacc518e2c55583a5fdad75993

openstack/training-labs,openstack/training-labs,openstack/training-labs