Description:
When VNC listen on IPV6 address, guest start up failed with qemu-kvm-rhev-2.3.0-1.el7.x86_64

Version-Release number of selected component (if applicable):
libvirt-1.2.16-1.el7.x86_64
qemu-kvm-rhev-2.3.0-1.el7.x86_64
3.10.0-259.el7.x86_64


How reproducible:
100%

Steps:
1. edit guest with below XML
# virsh edit rh7
...
<graphics type='vnc' port='-1' autoport='yes' listen='::1'>
      <listen type='address' address='::1'/>
    </graphics>
...

2. start guest failed with error

# virsh start rh7
error: Failed to start domain rh7
error: internal error: early end of file from monitor: possible problem:
2015-06-08T01:49:54.905220Z qemu-kvm: -vnc [::1]:0: Failed to start VNC server on `(null)': address resolution failed for [::1]:5900: Name or service not known


3. configure guest with VNC listen on ipv6 network, still failed

# virsh edit rh7
...
<graphics type='vnc' port='-1' autoport='yes'>
      <listen type='network' network='ipv6'/>
    </graphics>
...

# virsh start rh7
error: Failed to start domain rh7
error: internal error: early end of file from monitor: possible problem:
2015-06-08T01:51:35.437876Z qemu-kvm: -vnc [2001:b8:ca2:2::1]:0: Failed to start VNC server on `(null)': address resolution failed for [2001:b8:ca2:2::1]:5900: Name or service not known

# virsh net-dumpxml ipv6
<network>
  <name>ipv6</name>
  <uuid>7ba66277-91b2-45b0-810b-f3620b924790</uuid>
  <forward mode='nat'/>
  <bridge name='virbr6' stp='on' delay='0'/>
  <mac address='52:54:00:46:07:af'/>
  <ip family='ipv6' address='2001:b8:ca2:2::1' prefix='64'>
    <dhcp>
      <range start='2001:b8:ca2:2:1::10' end='2001:b8:ca2:2:1::ff'/>
    </dhcp>
  </ip>
</network>

4.on qemu-kvm-rhev-2.2.0-9.el7.x86_64,  guest start success . check qemu CML. VNC bound to [::1] success

# ps aux |grep rh7
qemu     10014 21.7  4.0 3769480 326780 ?      Sl   09:47   0:23 /usr/libexec/qemu-kvm -name rh7 -S -machine pc-i440fx-rhel7.1.0,accel=kvm,usb=off -cpu Penryn -m 1024 -realtime mlock=off ... -vnc [::1]:0 ...


Excepted results:

Guest should start success when VNC listen on IPV6 address 


Actual results:

Guest start failed when VNC listen on IPV6 address on qemu-kvm-rhev-2.3.0-1.el7.x86_64