libvirt-machine: Only gather stats in running state
libvirt-machine: Only gather stats in running state

There is no need to keep querying libvirt for stats/info on domain if
domain is not running. Doing so only wastes host resources and even
result in console getting spammed with warnings when host is under heavy
load.

https://bugzilla.gnome.org/show_bug.cgi?id=685900

vbenes/gnome-boxes,vbenes/gnome-boxes