Stop logging versions on every agent update

This logging statement was being called on every agent update
even if no versions changed, resulting in a bunch of useless
messages.

We already log when the actual versions change in the _set_version
call here: [1]

To cover the cases where versions are removed, this adds two logging
statements so we can be sure we see when the tracked versions do
change but not be bothered by version logs in any other condition.

1.
http://git.openstack.org/cgit/openstack/neutron/tree/neutron/api/rpc/callbacks/version_manager.py?h=d225b86738a9db56bc643dfe637b1f21393ad27e#n113

Partial-Bug: #1707307
Change-Id: I4761d21257dabfbd661bba1b24fe09d208d16ae6
(cherry picked from commit 03898582c8)

neutron/api/rpc/callbacks/version_manager.py

@@ -143,6 +143,9 @@ class ResourceConsumerTracker(object):
             self._versions_by_consumer[consumer].keys())
         cur_resource_types = set(versions.keys())
         removed_resource_types = prev_resource_types - cur_resource_types
+        if removed_resource_types:
+            LOG.debug("Removing stale tracked versions: %s",
+                      removed_resource_types)
         for resource_type in removed_resource_types:
             self._set_version(consumer, resource_type, None)
 
@@ -150,6 +153,7 @@ class ResourceConsumerTracker(object):
         """Handle consumers reporting no versions."""
         if self._versions_by_consumer[consumer]:
             self._needs_recalculation = True
+            LOG.debug("Clearing versions for consumer %s", consumer)
         self._versions_by_consumer[consumer] = {}
 
     def get_resource_versions(self, resource_type):

neutron/db/agents_db.py

@@ -429,9 +429,6 @@ class AgentDbMixin(ext_agent.AgentPluginBase, AgentAvailabilityZoneMixin):
             resource_versions = agent.get('resource_versions', {})
             consumer = version_manager.AgentConsumer(
                 agent_type=agent['agent_type'], host=agent['host'])
-            LOG.debug("Update consumer %(consumer)s versions to: "
-                      "%(versions)s", {'consumer': consumer,
-                                       'versions': resource_versions})
             tracker.set_versions(consumer, resource_versions)