This regression is caused by the following upstream patch

commit 6c477650ca3497eb56fa273a421f72d4d8f9aca1
Author: Jiri Denemark <Jiri.Denemark>
Date:   Mon May 23 12:15:05 2011 +0100

    Add support for listen attribute
    
    Virt-viewer now parses listen attribute from graphics element to be able
    to connect to domains configured with explicit listen address:
    
        <graphics type='vnc' port='-1' autoport='yes' listen='123.45.67.89'/>


The patch is fine in the case where the XML gives an explicit address, but for a wildcard address like 0.0.0.0 it clearly does not work.

In the latter case we'll need to fallback to use the hostname from the libvirt URI as with previous releases.

Note for testing, there are three guest configurations that should be tested

 1. No listen attribute

      <graphics type='vnc' port='-1' autoport='yes'/>

 2. Specific listen attribute

      <graphics type='vnc' port='-1' autoport='yes' listen='123.45.67.89'/>

 3. Wildcard listen attribute

      <graphics type='vnc' port='-1' autoport='yes' listen='0.0.0.0'/>


These need to be tested with two command lines:

 1. Tunnelled over ssh:

  virt-viewer -c qemu+ssh://root.and.domain/system vm-name

 2. Direct connection

  virt-viewer --direct -c qemu+ssh://root.and.domain/system vm-name

The issue 'virt-viewer --direct --connect' fails to connect remote vms' can reproduce on version:
virt-viewer-0.4.1-3.el6.x86_64

Verified on version:
virt-viewer-0.4.1-5.el6.x86_64

Environment:
kernel-2.6.32-191.el6.x86_64
libvirt-0.9.4-11.el6
python-virtinst-0.600.0-3.el6
qemu-kvm-0.12.1.2-2.185.el6
virt-manager-0.9.0-6.el6
virt-viewer-0.4.1-5.el6.x86_64

Prepared two host and a remote vm:
local host
remote host 
remote vm named xpi386

Detail Steps:
1.Make sure local host has no running vm.
logon the local host:
#virt-viewer --direct --connect=qemu+ssh://remotehostIP/system xpi386

There will be an error pop-up:"Unable to connect to the graphic server
0.0.0.0:5900"

2.If there is an vm running on local host,
#virsh dumpmxl win2008x64
...
<graphics type='vnc' port='5900' autoport='yes'/>
...
#virt-viewer --direct --connect=qemu+ssh://remotehostIP/system xpi386
Then the vm 'win2008x64' on the local host will be opened.

3. No listen attribute:
#virsh dumpmxl xpi386
<graphics type='vnc' port='-1' autoport='yes'/>
logon the local host:
a. #virt-viewer -c qemu+ssh://root@remotehostIP/system xpi386
The remote vm 'xpi386' opened successfully through virt-viewer.
b. #virt-viewer --direct -c qemu+ssh://root@remotehostIP/system xpi386
The remote vm 'xpi386' can not open,error pop up: "Unable to connect to the graphic server localhost:5900"
logon the remote host:
#virt-viewer --direct -c qemu+ssh://root@remotehostIP/system xpi386
The remote vm 'xpi386' opened successfully through virt-viewer.

4. Specific listen attribute:
#virsh dumpmxl xpi386
<graphics type='vnc' port='-1' autoport='yes' listen='10.66.6.23'/>
<listen type='address' address='10.66.6.23'/>

logon the local host:
#virt-viewer -c qemu+ssh://root@remotehostIP/system xpi386
#virt-viewer --direct -c qemu+ssh://root@remotehostIP/system xpi386
The remote vm 'xpi386' opened successfully through virt-viewer.

5. Wildcard listen attribute:
#virsh dumpmxl xpi386
<graphics type='vnc' port='-1' autoport='yes' listen='0.0.0.0'>
<listen type='address' address='0.0.0.0'/>

logon on the local host:
#virt-viewer -c qemu+ssh://root@remotehostIP/system xpi386
#virt-viewer --direct -c qemu+ssh://root@remotehostIP/system xpi386
The remote vm 'xpi386' opened successfully through virt-viewer.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHEA-2011-1614.html