Improve error message from 'virt-sandbox-service delete'
Improve error message from 'virt-sandbox-service delete'

When the sandbox was already deleted, the virt-sandbox-service
returned a "no such file or directory" error message. Change
that to explicitly tell the user the sandbox was deleted.

Signed-off-by: Daniel P. Berrange <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

agx/libvirt-sandbox-debian,erenyagdiran/libvirt-sandbox,gczarcinski/libvirt-sandbox,gczarcinski/libvirt-sandbox,gczarcinski/libvirt-sandbox,gczarcinski/libvirt-sandbox,gczarcinski/libvirt-sandbox,libvirt/libvirt-sandbox,libvirt/libvirt-sandbox,agx/libvirt-sandbox-debian,agx/libvirt-sandbox-debian,erenyagdiran/libvirt-sandbox,libvirt/libvirt-sandbox,erenyagdiran/libvirt-sandbox,agx/libvirt-sandbox-debian,gczarcinski/libvirt-sandbox,agx/libvirt-sandbox-debian,erenyagdiran/libvirt-sandbox