Maybe this should help to sort it out "forever"?

commit 0e4370eddf822fcdd2ed60d7326b2191e1fd948d
Author: Matthias Bolte <matthias.bolte>
Date:   Sat May 10 16:36:56 2014 +0200

    vmx: Relax virtualHW.version check
    
    The original implementation of the VMX config parser assumed that the
    virtualHW.version would have more influence on the content of the VMX
    file than it actually seems to have. It started with accepting only
    version 4. Additonal versions were added later without any additional
    changes in the parser itself. This suggests that the influence of the
    virtualHW.version on the content and format of the VMX file is small
    or non-existent.
    
    The parser worked without any changes across several virtualHW and
    vSphere versions. So instead of adding new virtualHW.version values to
    the parser as they come along, or adding an extra flag to allow unknown
    virtualHW.version values just relax the check to require version 4 or
    later.

I can reproduced the bug with build:
libvirt-0.10.2-56.el6.x86_64

Try to verfiy the bug with build:
libvirt-0.10.2-57.el6.x86_64


Steps:
1.Prepare a VM from an esx host that has hardware version 11.
2.Use virsh to connect the esx host.
# virsh -c esx://10.66.144.40/?no_verify=1
Enter username for 10.66.144.40 [root]: 
Enter root's password for 10.66.144.40: 
Welcome to virsh, the virtualization interactive terminal.

Type:  'help' for help with commands
       'quit' to quit

virsh # list --all
 Id    Name                           State
----------------------------------------------------
 1     win2012R2-vcenter              running
 -     rhel5.11-mxie                  shut off
 -     rhel6.7-mxie                   shut off
 -     test-juzhou                    shut off
 -     test-rhel6u6-x64               shut off

3.Use virsh dumpxml to get the xml of the vm with virtualHW.version 11.
virsh # dumpxml test-rhel6u6-x64
<domain type='vmware'>
  <name>test-rhel6u6-x64</name>
  <uuid>421c4727-c7aa-8bfc-1557-b5ac56e75608</uuid>
  <memory unit='KiB'>1048576</memory>
  <currentMemory unit='KiB'>1048576</currentMemory>
  <vcpu placement='static'>1</vcpu>
  <cputune>
    <shares>1000</shares>
  </cputune>
  <os>
    <type arch='x86_64'>hvm</type>
  </os>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <devices>
    <disk type='file' device='disk'>
      <source file='[datastore1] test-rhel6u6-x64/test-rhel6u6-x64.vmdk'/>
      <target dev='sda' bus='scsi'/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>
    <controller type='scsi' index='0' model='vmpvscsi'/>
    <interface type='bridge'>
      <mac address='00:50:56:9c:58:9c'/>
      <source bridge='VM Network'/>
      <model type='vmxnet3'/>
    </interface>
    <video>
      <model type='vmvga' vram='8192'/>
    </video>
  </devices>
</domain>

Result now:
Libvirt support dumpxml for esx guest with virtualHW.version 11 now

So move the bug from ON_QA to VERIFIED

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.

https://rhn.redhat.com/errata/RHBA-2016-0738.html