Fix KeyError exception upon  service/deployment deletion
When service/deployment being deleted KeyError exception is reported,
this patch solve this issue.
Closes-Bug:
@@ -305,7 +305,8 @@ class LoadBalancerHandler(k8s_base.ResourceEventHandler):
continue
except KeyError:
continue
-
+ if not pool_by_tgt_name:
+ continue
for subset_port in subset_ports:
target_port = subset_port['port']
if (target_ip, target_port) in current_targets:
