Description of problem:
 when use ssh connect guest ,the usb-device redirection can't worked.

Version-Release number of selected component (if applicable):
virt-viewer-0.5.2-6.el6.x86_64
libvirt-0.9.10-14.el6.x86_64
qemu-kvm-0.12.1.2-2.267.el6.x86_64
spice-gtk-0.11-8.el6.x86_64
spice-server-0.10.1-5.el6.x86_64
usbredir-0.4.3-1.el6.x86_64
kmod-kspiceusb-rhel60-4.9-14.el6.x86_64
spice-usb-share-4.9-9.el6.x86_64

How reproducible:
100%

Steps to Reproduce:
1: prepare two host
2: config ssh between the two machine
in one box:
#ssh-keygen
#ssh-copy-id -i /root/.ssh/id_rsa.pub root@$remote_IP
3: prepare a windows guest with usb-redirection support
3.1 Download the .cfg file to /etc/qemu:
# wget http://cgit.freedesktop.org/spice/qemu/plain/docs/ich9-ehci-uhci.cfg

3.2 config guest xml :
<domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
And add the following lines at the end, above the "</domain>" line:
  <qemu:commandline>
     <qemu:arg value='-readconfig'/>
     <qemu:arg value='/etc/qemu/ich9-ehci-uhci.cfg'/>
     <qemu:arg value='-chardev'/>
     <qemu:arg value='spicevmc,name=usbredir,id=usbredirchardev1'/>
     <qemu:arg value='-device'/>
     <qemu:arg value='usb-redir,chardev=usbredirchardev1,id=usbredirdev1,bus=ehci.0,debug=3'/>
     <qemu:arg value='-chardev'/>
     <qemu:arg value='spicevmc,name=usbredir,id=usbredirchardev2'/>
     <qemu:arg value='-device'/>
     <qemu:arg value='usb-redir,chardev=usbredirchardev2,id=usbredirdev2,bus=ehci.0,debug=3'/>
     <qemu:arg value='-chardev'/>
     <qemu:arg value='spicevmc,name=usbredir,id=usbredirchardev3'/>
     <qemu:arg value='-device'/>
     <qemu:arg value='usb-redir,chardev=usbredirchardev3,id=usbredirdev3,bus=ehci.0,debug=3'/>
  </qemu:commandline>
4: make sure in guest ,the Red hat usb redirector service started.
5: in another host , use ssh to connect the guest
# virt-viewer -c qemu+ssh://10.66.6.166/system win7_64
6: in virt-viewer, click "File"->"USB Device selection"

Actual results:
the device can't mount to the guest.

Expected results:
the usb device can redirect to the guest.

Additional info:
if not use ssh connection, the usb-device can worked well.
in this ssh env. ,the smartcard can worked well.