Drop needless virtType validation

Drop needless virtType validation

This code originates from:

commit d0aa10fdd6c108ad442886e4451b2629a3dc8b86
Author: Daniel P. Berrange <berrange@redhat.com>
Date:   Tue Mar 3 12:03:44 2009 +0000

    QEMU security driver usage for sVirt support (James Morris, Dan Walsh, Daniel Berrange)

Originally in the qemudDomainGetSecurityLabel function. It doesn't
appear to have done anything useful back then either. The other two
instances look like copy+paste

Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>