userfailtfd.h is used by post-copy migration so include it to
the update-linux-headers.sh as we want it updated altogether with
other kernel headers.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Message-Id: <1455512381-15271-1-git-send-email-aik@ozlabs.ru>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>