Fix neutron agent client

Change-Id: I21f5712d0bad3d617ddf3c50f963d369bb09d5a8
diff --git a/openstack/networking/v2/extensions/agents/requests.go b/openstack/networking/v2/extensions/agents/requests.go
index 5c6433e..79e50dd 100644
--- a/openstack/networking/v2/extensions/agents/requests.go
+++ b/openstack/networking/v2/extensions/agents/requests.go
@@ -8,6 +8,6 @@
 func List(c *gophercloud.ServiceClient) pagination.Pager {
 	u := listURL(c)
 	return pagination.NewPager(c, u, func(r pagination.PageResult) pagination.Page {
-		return AgentPage{pagination.LinkedPageBase{PageResult: r}}
+		return AgentPage{pagination.SinglePageBase(r)}
 	})
 }