webadmin: Conform QuotaListModel to standard

- Fixed QuotaListModel to have the same command method
names as all the other models. Some functionality is dependent
on the fact that all Models follow the same convention.

Change-Id: Ieb9a4ede386d494399855181f0a4ef58542253c7
Signed-off-by: Alexander Wels <awels@redhat.com>