The quota-class-update commands for v1 and v2 are both broken,
Fix v1 by returning result for update method in QuotaClassSetManager,
fix v2 by changing arg 'class-name' to 'class_name' for consistent
with v1.
Change-Id: Ic7188f485b914dc55048cf056a0685618134e87a
Closes-bug: #1423884