The Securty Group name should be unique

Currently the service's name is not unique, and the Securty Group
name is not unique too. openstack cloud provider will delete the
Securty Group of other loadbalancer service when do a deletion.

pkg/cloudprovider/providers/openstack/openstack_loadbalancer.go

@@ -372,7 +372,7 @@ func popMember(members []v2pools.Member, addr string, port int) []v2pools.Member
 }
 
 func getSecurityGroupName(clusterName string, service *v1.Service) string {
-	return fmt.Sprintf("lb-sg-%s-%v", clusterName, service.Name)
+	return fmt.Sprintf("lb-sg-%s-%s-%s", clusterName, service.Namespace, service.Name)
 }
 
 func getSecurityGroupRules(client *gophercloud.ServiceClient, opts rules.ListOpts) ([]rules.SecGroupRule, error) {