Added ability to remove networks on nova-manage command

bin/nova-manage

@@ -548,6 +548,10 @@ class NetworkCommands(object):
     def delete(self, fixed_range):
         """Deletes a network"""
         network = db.network_get_by_cidr(context.get_admin_context(), fixed_range)
+        if network.project_id is not None:
+            raise ValueError(_('Network must be disassociated from project %s' 
+                               ' before delete' %network.project_id))
+        db.network_delete_safe(context.get_admin_context(), network.id)  
   
 class ServiceCommands(object):
     """Enable and disable running services"""