Agent manager raises KeyError exception during load balancer sync (#1233

)

Issues:
Fixes #1228

Problem: Agent manger raises KeyError exception when it deletes
a LB ID that is no longer in collection of pending services.

Analysis: Added try/except block to catch KeyError and log exception.

Tests: Tempest tests

f5_openstack_agent/lbaasv2/drivers/bigip/agent_manager.py

@@ -647,7 +647,11 @@ def _refresh_pending_services(self):
                     self.service_timeout(lb_id)
 
             if not lb_pending:
-                del self.pending_services[lb_id]
+                try:
+                    del self.pending_services[lb_id]
+                except KeyError as e:
+                    LOG.error("LB not found in pending services: {0}".format(
+                        e.message))
 
         # If there are services in the pending cache resync
         if self.pending_services: