These errors don't seem user initiated, so forcibly printing to the
monitor doesn't seem right. Just use error_report.

Cc: Anthony Liguori <aliguori@amazon.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>