Description of problem:
virt-manager should support spice multihead

Version-Release number of selected component (if applicable):
virt-manager-0.9.0-6.el6


How reproducible:
always

Steps to Reproduce:
  1:Install a new Windows XP guest
  2:Change the guest to use SPICE graphics and have a single QXL video card
  3:Boot the guest, and install the WHQL'd 'QXL' driver in Windows.
  4:Reboot the guest and check QXL is working properly
  5:Shutdown the guest
  6:Add another 'video' element to the guest XML
  #virsh dumpxml winxp
.......
 <graphics type='spice' port='5900' tlsPort='-1' autoport='yes'
listen='0.0.0.0'>
      <listen type='address' address='0.0.0.0'/>
    </graphics>
    <video>
      <model type='qxl' vram='65536' heads='1'/>
      <alias name='video0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02'
function='0x0'/>
    </video>
    <video>
      <model type='qxl' vram='65536' heads='1'/>
      <alias name='video1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06'
function='0x0'/>
    </video>
.......
   7: Boot the guest again, and make sure Windows installs the QXL driver for
the new graphics card
   8:in Windows XP guest,right click on the desktop,in
"settings"->"Display",list two monitor on "Red Hat QXL GPU"
   9: select the second monitor,checked "Extend my Windows desktop onto this
monitor" and apply
  10: #virt-manager
  11: in virt-manager , open the guest
Actual results:
  only open one graphic console

Expected results:
  support spice multi-head ,will open two graphic console,same behavior with 
using virt-viewer.

Additional info: