actions-popover: No open_in_new_win from own window
actions-popover: No open_in_new_win from own window

When a machine is already running in a separate window, clicking on 'Open
in New Window' simply brings up its window so it doesn't actually do
anything if this option is choosen from machine's window itself. Lets
just not show this useless option in that case.

https://bugzilla.gnome.org/show_bug.cgi?id=744434

vbenes/gnome-boxes,vbenes/gnome-boxes