the testcases related to agent mode in libvirt with windows guest os run failed

[lijuanmen]

The testcases in libvirt were runned with win7 and win2012 guest os. All of them related to agent mode runned failed.

In the py file(eg,virsh_reboot.py),the code about agent is as followed in general：
if agent:
vm_xml.VMXML.set_agent_channel(vm_name)
else:
vm_xml.VMXML.remove_agent_channel(vm_name)

    virsh.start(vm_name)
    guest_session = vm.wait_for_login()
    if agent:
        guest_session.cmd("qemu-ga -d")
        stat_ps = guest_session.cmd_status("ps aux |grep [q]emu-ga")
        guest_session.close()
        if stat_ps:
            raise error.TestError("Fail to start qemu-guest-agent!")

The windows guest os doesn`t support these linux command ,so the testcases related to agent mode run failed.