Add a comment for a workload in rally-neutron.yaml
Add a comment for a workload in rally-neutron.yaml

VMTasks.boot_runcommand_delete scenario with image_command_customizer
are the powerful mechanism for creating useful workloads.
One of such workload can muslead by it configuration, so this patch adds
a comment to it.

Change-Id: I84696ca029077063118a161e4f3d1933ea131877

openstack/rally,openstack/rally,openstack/rally,openstack/rally