Re: [libvirt] PATCH: Fix crash / cleanup bugs in sVirt verification

If defining a VM without any <seclabel> element present, the new verification code will crash as it deferences NULL, so we just need to skip over that. Second, if one does a roundtrip of a live VM config virsh dumpxml foo > foo.xml virsh define foo.xml and then stop and start the guest, it will now fail complaining that the security label is already defined. This is because the XML parser is mistakenly parsing the 'model' attribute even for VMs whose label is defined to be dynamic. This then exposed anothe bug in the qemudStartVMDaemon() method where it would not properly cleanup after a failed launch, failing to reset the dynamic allocated security label, and also failing to close a logfil file descriptor.