Don't change Dell Equallogic san_thin_provision

At the request of Rajini Ram from Dell, the comment that suggests
changing san_thin_provision to 'False' should be 'True' for best
practice.

This is already in effect in Juno (which changed this driver reference),
so this patch is just for icehouse.

Change-Id: I402863d73d700293e92dc0a88b9e405b37aabaef
Closes-Bug: 1384927