Update eventlet API in libvirt driver
Update eventlet API in libvirt driver

Stop using the deprecated eventlet.util API: use
eventlet.patcher.original('socket') to access the original socket.socket
type.

Conflicts:
        nova/virt/libvirt/host.py

NOTE(mriedem): The conflict is due to the host module being
newly refactored out of the driver module in Kilo.

Change-Id: Idbb9d2b53829dae0e807cd1260dee3dce155d5f3
Closes-Bug: 1407685
(cherry picked from commit 5793aff19033dd53cefa97fced64a4bf95ea0c72)

redhat-openstack/nova,tianweizhang/nova,redhat-openstack/nova,tianweizhang/nova