Add events and resources for L3 flavors.

To address the callbacks in L3 flavor drivers for OpenDaylight
new event and resources are added to handle router request.
They are introduced initially in neutron [1]. but neutron-lib
is the right place to have them.

[1].https://review.openstack.org/#/c/523257/

Change-Id: I1e72ee843851004d26410a90da4030ab3b024741

neutron_lib/callbacks/events.py

@@ -19,6 +19,8 @@ BEFORE_DELETE = 'before_delete'
 PRECOMMIT_CREATE = 'precommit_create'
 PRECOMMIT_UPDATE = 'precommit_update'
 PRECOMMIT_DELETE = 'precommit_delete'
+PRECOMMIT_ADD_ASSOCIATION = 'precommit_add_association'
+PRECOMMIT_DELETE_ASSOCIATIONS = 'precommit_delete_associations'
 
 AFTER_CREATE = 'after_create'
 AFTER_READ = 'after_read'

neutron_lib/callbacks/resources.py

@@ -22,6 +22,7 @@ PORT_DEVICE = 'port_device'
 PROCESS = 'process'
 RBAC_POLICY = 'rbac-policy'
 ROUTER = 'router'
+ROUTER_CONTROLLER = 'router_controller'
 ROUTER_GATEWAY = 'router_gateway'
 ROUTER_INTERFACE = 'router_interface'
 SECURITY_GROUP = 'security_group'

releasenotes/notes/events_l3_flavors-053714858ced693d.yaml

@@ -0,0 +1,4 @@
+---
+features:
+  - This adds two new events ``PRECOMMIT_ADD_ASSOCIATION``,
+    ``PRECOMMIT_DELETE_ASSOCIATIONS`` and a resource ``ROUTER_CONTROLLER``.