Add unit test case in Nimble Driver
Add unit test case in Nimble Driver

Cinder drivers have test case about getting manage volume size, like lvm,
rbd, emc and so on. But nimble driver lacks the case. This patch fixes
it by adding test_manage_volume_get_size test case.

Change-Id: Iccfcb409381bd35ea034cd8904ab4826f6a56b49
Closes-Bug: #1587306

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