virsh: Honour -q in domblklist, vcpupin and emulatorpin
    
    If user wants to grep some info from domain, e.g. disk paths:
    
        # virsh -q domblklist win7 | awk '{print $2}'
        Source
    
        /var/lib/libvirt/images/windows.qcow2
        /home/zippy/work/tmp/en_windows_7_professional_x64_dvd_X15-65805.iso
    
    while with my change:
    
        # virsh -q domblklist win7 | awk '{print $2}'
        /var/lib/libvirt/images/windows.qcow2
        /home/zippy/work/tmp/en_windows_7_professional_x64_dvd_X15-65805.iso
    
    We don't print table header in other commands, like list.
    
    Signed-off-by: Michal Privoznik <mprivozn@redhat.com>