Fix VMware settings

https://review.openstack.org/#/c/61520 had a pasto in it.
The change was "Clarified details of volume driver configuration
settings for VMDK drivers in nova.conf and cinder.conf."
But the change itself was in both cases the same line for cinder.conf.
Fix the nova.conf setting.

Change-Id: I4a5f201d3724aa25c0a752696860cd718124443b
backport: havana
Merge "Fix VMware settings"