Fix crash free'ing securityDriverNames in QEMU driver
Fix crash free'ing securityDriverNames in QEMU driver

The previous fix to avoid leaking securityDriverNames forgot to
handle the case of securityDriverNames being NULL, leading to
a crash

Signed-off-by: Daniel P. Berrange <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

VenkatDatta/libvirt,VenkatDatta/libvirt,jfehlig/libvirt,rlaager/libvirt,zippy2/libvirt,zhlcindy/libvirt-1.1.4-maintain,cbosdo/libvirt,fabianfreyer/libvirt,shugaoye/libvirt,cbosdo/libvirt,jardasgit/libvirt,VenkatDatta/libvirt,eskultety/libvirt,eskultety/libvirt,eskultety/libvirt,elmarco/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,zhlcindy/libvirt-1.1.4-maintain,siboulet/libvirt-openvz,agx/libvirt,taget/libvirt,zhlcindy/libvirt-1.1.4-maintain,olafhering/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,trainstack/libvirt,zhlcindy/libvirt-1.1.4-maintain,andreabolognani/libvirt,jardasgit/libvirt,elmarco/libvirt,rlaager/libvirt,siboulet/libvirt-openvz,jfehlig/libvirt,elmarco/libvirt,siboulet/libvirt-openvz,jardasgit/libvirt,zippy2/libvirt,zippy2/libvirt,VenkatDatta/libvirt,iam-TJ/libvirt,cbosdo/libvirt,iam-TJ/libvirt,shugaoye/libvirt,taget/libvirt,siboulet/libvirt-openvz,rlaager/libvirt,shugaoye/libvirt,taget/libvirt,cbosdo/libvirt,elmarco/libvirt,olafhering/libvirt,trainstack/libvirt,jardasgit/libvirt,zippy2/libvirt,crobinso/libvirt,eskultety/libvirt,nertpinx/libvirt,crobinso/libvirt,taget/libvirt,rlaager/libvirt,iam-TJ/libvirt,trainstack/libvirt,agx/libvirt,datto/libvirt,elmarco/libvirt,iam-TJ/libvirt,iam-TJ/libvirt,iam-TJ/libvirt,crobinso/libvirt,iam-TJ/libvirt,rlaager/libvirt,agx/libvirt,datto/libvirt,andreabolognani/libvirt,libvirt/libvirt,libvirt/libvirt,andreabolognani/libvirt,trainstack/libvirt,trainstack/libvirt,trainstack/libvirt,fabianfreyer/libvirt,agx/libvirt,agx/libvirt,libvirt/libvirt,trainstack/libvirt,datto/libvirt,shugaoye/libvirt,jfehlig/libvirt,cbosdo/libvirt,datto/libvirt,libvirt/libvirt,siboulet/libvirt-openvz,nertpinx/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,datto/libvirt,nertpinx/libvirt,shugaoye/libvirt,nertpinx/libvirt,andreabolognani/libvirt,taget/libvirt,crobinso/libvirt,zhlcindy/libvirt-1.1.4-maintain,eskultety/libvirt,jardasgit/libvirt,VenkatDatta/libvirt,olafhering/libvirt,olafhering/libvirt