remove unused quotas code

This code is not used anywhere, removing.

Change-Id: I526b8c13e6f5ad8d441f219bb4dca36c0377adfe
Implements: blueprint make-quotas-great-again

openstack_dashboard/usage/base.py

@@ -23,7 +23,6 @@ from horizon import forms
 from horizon import messages
 
 from openstack_dashboard import api
-from openstack_dashboard.usage import quotas
 
 
 class BaseUsage(object):
@@ -239,13 +238,6 @@ class BaseUsage(object):
                 self.summary.setdefault(key, 0)
                 self.summary[key] += value
 
-    def get_quotas(self):
-        try:
-            self.quotas = quotas.tenant_quota_usages(self.request)
-        except Exception:
-            exceptions.handle(self.request,
-                              _("Unable to retrieve quota information."))
-
     def csv_link(self):
         form = self.get_form()
         data = {}