1.1 Liberty - Nova compute failed to connect libvirt
在M版FIX了，L版的临时解决方法是：
Openstack-nova-compute is service on compute node.
So, on Ubuntu, CentOS 6.5 :
# service openstack-nova-compute restart # service openstack-nova-compute status
on CentOS 7, Fedora 20
# systemctl restart openstack-nova-compute # systemctl status openstack-nova-compute