NetApp: Fix SSH Client File Creation in Unit Test
NetApp: Fix SSH Client File Creation in Unit Test

A bug was introduced where ssh_known_hosts file is created when the unit
tests in test_netapp.py are run. This patch adds mocks to the ssh init
calls to prevent this file creation.

Change-Id: Ie8ac4e7a5236e6735c7c2f4f50c5383f5f23d38e
Closes-bug: #1550542

Hybrid-Cloud/cinder,phenoxim/cinder,cloudbase/cinder,Datera/cinder,Datera/cinder,bswartz/cinder,eharney/cinder,mahak/cinder,openstack/cinder,phenoxim/cinder,cloudbase/cinder,NetApp/cinder,ge0rgi/cinder,eharney/cinder,Nexenta/cinder,mahak/cinder,j-griffith/cinder,openstack/cinder,j-griffith/cinder,Nexenta/cinder,NetApp/cinder,bswartz/cinder,Hybrid-Cloud/cinder