openxenmanager, cant perform host shutdown through right click after starting vm

[Andy Brook]

Reproduction steps:
1. Start a vm
2. Use right click to try and shut it down

Outcome:
  File "window.py", line 1335, in on_treevm_button_press_event
    self.update_tabs()
  File "window.py", line 670, in update_tabs
    self.xc_servers[self.selected_host].update_tab_vm_general(self.selected_ref, self.builder)
  File "/usr/share/openxenmanager/oxcSERVER.py", line 1687, in update_tab_vm_general
    if "name" in guest_metrics["os_version"]:
KeyError: 'os_version'

If I restart openxenman, then it works, so is somehow related to vm actions.

I noticed that the problem isn't immediate, I can start a vm, still have the options to shutdown for a while, then it breaks

Affects versions (dpkg -l)
ii openxenmanager 0.r80+dfsg-4 all full-featured graphical management tool for xen using xenapi