Description of problem:
boot a guest with vnc :d,password option and set a password for vnc. after migrate,vncview cann't use the same password to login guest.

Version-Release number of selected component (if applicable):
# rpm -qa|grep kvm
kvm-83-246.el5
# uname -r
2.6.18-300.el5

How reproducible:
always

Steps to Reproduce:
1./usr/libexec/qemu-kvm  -M rhel5.6.0 -m 4096 -smp 4,cores=2,threads=1,sockets=2 -cpu qemu64,vendor="AuthenticAMD",+sse2 -soundhw all -name win7 -usbdevice tablet -rtc-td-hack -uuid 123465d2-2032-848d-bda0-de7adb149048 -boot c -drive file=/home/rhel6.2.z-64.qcow2,if=virtio,boot=on,bus=0,unit=0,format=qcow2,cache=none,boot=on,werror=stop -net nic,macaddr=54:52:00:27:12:23,vlan=0,model=virtio -net tap,vlan=0,script=/etc/qemu-ifup -serial pty -parallel none -usb -balloon none -monitor stdio -vnc :1,password

2.change vnc password
(qemu) change vnc password
Password:123456

3.boot des guest
/usr/libexec/qemu-kvm  -M rhel5.6.0 -m 4096 -smp 4,cores=2,threads=1,sockets=2 -cpu qemu64,vendor="AuthenticAMD",+sse2 -soundhw all -name win7 -usbdevice tablet -rtc-td-hack -uuid 123465d2-2032-848d-bda0-de7adb149048 -boot c -drive file=/home/rhel6.2.z-64.qcow2,if=virtio,boot=on,bus=0,unit=0,format=qcow2,cache=none,boot=on,werror=stop -net nic,macaddr=54:52:00:27:12:23,vlan=0,model=virtio -net tap,vlan=0,script=/etc/qemu-ifup -serial pty -parallel none -usb -balloon none -monitor stdio -vnc :1,password -incoming tcp:0:5555

4.migrate
(qemu) migrate -d tcp:10.66.9.97:5555

5.use vncview and password(123456) to connect des guest 
  vncviewer 10.66.9.97:5901

Actual results:
authentication failed

Expected results:
vncview login des guest successful 


Additional info:
rhel6.2 host have the issue.