Description of problem:
Start a guest with spice/vnc listening on 0.0.0.0, connect to libvirtd by IPv6 address on a remote host, and check domdisplay, it shows IPv6 address wrongly:
# virsh -c qemu+ssh://[2002::1]/system domdisplay rhel7
spice://[2002::1]:5900

Version-Release number of selected component (if applicable):
libvirt-2.0.0-10.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
0. Prepare two hosts with IPv6 address:
   On host A: # ifconfig eth0 add 2002::1/64
   On host B: # ifconfig eth0 add 2002::2/64

1. On host A:
Start a guest with spice/vnc listening on 0.0.0.0
# virsh start rhel7

# virsh dumpxml rhel7
...
    <graphics type='spice' port='5900' autoport='yes' listen='0.0.0.0'>
      <listen type='address' address='0.0.0.0'/>
    </graphics>
...

# netstat -tunap|grep 5900
tcp        0      0 0.0.0.0:5900            0.0.0.0:*               LISTEN      2178/qemu-kvm  

2. On host B:
1) Connect to remote libvirtd with IPv6 address and check domdisplay
# virsh -c qemu+ssh://[2002::1]/system domdisplay rhel7
spice://[2002::1]:5900

2) Connect to remote libvirtd with IPv4 address and check domdisplay
# virsh -c qemu+ssh://10.66.4.152/system domdisplay rhel7
spice://10.66.4.152:5900

Actual results:
In step 2-1, Virsh domdisplay returns IPv6 address while qemu is listening on IPv4

Expected results:
Virsh domdisplay can always return correct URI