By default, Data ONTAP sets the snapshot reserve for a share to
5%. Some users have requested a facility to override the default
for applications where snapshots aren't required. This commit adds
a config option for setting a different snap reserve value for a
specific cDOT backend.
Change-Id: Iba0bf696035353fac87f445f690bb94fa00ae0a0
Implements: blueprint netapp-cdot-snap-reserve-config-option
11ef510229