Implied by QEMU >= 1.2.0.

Delete this one first, because QEMU_CAPS_NODEFCONFIG is only used
when QEMU_CAPS_NO_USER_CONFIG is unsupported.
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NAndrea Bolognani <abologna@redhat.com>