Empty host subject from qemu should only validate hostname
Empty host subject from qemu should only validate hostname

Validate empty host subject from qemu exactly like when no explicit
host subject is specified.

https://bugzilla.redhat.com/show_bug.cgi?id=858228

freedesktop-unofficial-mirror/spice__spice-gtk,elmarco/spice-gtk,guodong/spice-gtk,elmarco/spice-gtk,guodong/spice-gtk,elmarco/spice-gtk,mathslinux/spice-gtk,mathslinux/spice-gtk,elmarco/spice-gtk,SPICE/spice-gtk,mathslinux/spice-gtk,SPICE/spice-gtk,Fantu/spice-gtk,flexVDI/spice-gtk,SPICE/spice-gtk,flexVDI/spice-gtk,fgouget/spice-gtk,freedesktop-unofficial-mirror/spice__spice-gtk,mathslinux/spice-gtk,SPICE/spice-gtk,freedesktop-unofficial-mirror/spice__spice-gtk,fgouget/spice-gtk,guodong/spice-gtk,freedesktop-unofficial-mirror/spice__spice-gtk,guodong/spice-gtk,fgouget/spice-gtk,Fantu/spice-gtk,Fantu/spice-gtk,Fantu/spice-gtk