Fix Bug Unable to get scoped data model

This patch removes 'audit_scope' from __init__ of
BaseClusterDataModelCollector class, as it is a singleton class
and cannot be instantiate more than once.

A new method is defined in BaseClusterDataModelCollector in place
of property audit_scope_handler, which takes audit_scope as
argument.

Change-Id: I0664c151d71a711c118d43c180d8b0760b1c81fa
Closes-Bug: #1732849

watcher/decision_engine/model/collector/cinder.py

@@ -37,10 +37,6 @@ class CinderClusterDataModelCollector(base.BaseClusterDataModelCollector):
     def __init__(self, config, osc=None):
         super(CinderClusterDataModelCollector, self).__init__(config, osc)
 
-    @property
-    def audit_scope_handler(self):
-        return None
-
     @property
     def notification_endpoints(self):
         """Associated notification endpoints
@@ -58,6 +54,9 @@ class CinderClusterDataModelCollector(base.BaseClusterDataModelCollector):
             cinder.VolumeResizeEnd(self)
         ]
 
+    def get_audit_scope_handler(self, audit_scope):
+        return None
+
     def execute(self):
         """Build the storage cluster data model"""
         LOG.debug("Building latest Cinder cluster data model")