docs: correct libvirt sandbox command naming
docs: correct libvirt sandbox command naming

Signed-off-by: Alex Jia <e236faec8cb8371bfb245ba3769a84afc9a11438@redhat.com>

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