Fix and skip gate failures

lower-constraints.txt is updated.
- ryu 4.24
- pecan 1.3.2

neutron-vpnaas-tempest-libreswan-centos is now non-voting
because Cinder DB migration fails on CentOS 7.

This patch also includes the changes from [1] as without them the tests
fail.

[1] https://review.openstack.org/#/c/599034/

Related-Bug: 1808709

Change-Id: Id6a2eadfacb3983cfc05142860a827d3233561dd

.zuul.yaml

@@ -13,7 +13,9 @@
       jobs:
         - neutron-vpnaas-dsvm-functional-sswan
         - neutron-vpnaas-tempest
-        - neutron-vpnaas-tempest-libreswan-centos
+        - neutron-vpnaas-tempest-libreswan-centos:
+            # Cinder DB migration fails on CentOS 7 (bug 1808709)
+            voting: false
     gate:
       jobs:
         - neutron-vpnaas-dsvm-functional-sswan

lower-constraints.txt

@@ -87,7 +87,7 @@ paramiko==2.0.0
 Paste==2.0.2
 PasteDeploy==1.5.0
 pbr==2.0.0
-pecan==1.0.0
+pecan==1.3.2
 pep8==1.5.7
 pika==0.10.0
 pika-pool==0.1.3
@@ -122,7 +122,7 @@ requests-mock==1.2.0
 requestsexceptions==1.2.0
 rfc3986==0.3.1
 Routes==2.3.1
-ryu==4.14
+ryu==4.24
 simplejson==3.5.1
 six==1.10.0
 snowballstemmer==1.2.1

neutron_vpnaas/db/vpn/vpn_db.py

@@ -693,22 +693,7 @@ class VPNPluginRpcDbMixin(object):
                         conn['updated_pending_status'])
 
 
-def vpn_callback(resource, event, trigger, **kwargs):
-    # TODO(boden): refactor back into single method once everything is using
-    # the event payload objects
-    vpn_plugin = directory.get_plugin(p_constants.VPN)
-    if vpn_plugin:
-        context = kwargs.get('context')
-        router_id = kwargs.get('router_id')
-        if resource == resources.ROUTER_GATEWAY:
-            vpn_plugin.check_router_in_use(context, router_id)
-        elif resource == resources.ROUTER_INTERFACE:
-            subnet_id = kwargs.get('subnet_id')
-            vpn_plugin.check_subnet_in_use(context, subnet_id, router_id)
-
-
 def vpn_router_gateway_callback(resource, event, trigger, payload=None):
-    # TODO(boden): refactor back into single method once everything is using
     # the event payload objects
     vpn_plugin = directory.get_plugin(p_constants.VPN)
     if vpn_plugin:
@@ -716,6 +701,9 @@ def vpn_router_gateway_callback(resource, event, trigger, payload=None):
         router_id = payload.resource_id
         if resource == resources.ROUTER_GATEWAY:
             vpn_plugin.check_router_in_use(context, router_id)
+        elif resource == resources.ROUTER_INTERFACE:
+            subnet_id = payload.metadata.get('subnet_id')
+            vpn_plugin.check_subnet_in_use(context, subnet_id, router_id)
 
 
 def migration_callback(resource, event, trigger, **kwargs):
@@ -741,7 +729,8 @@ def subscribe():
         vpn_router_gateway_callback, resources.ROUTER_GATEWAY,
         events.BEFORE_DELETE)
     registry.subscribe(
-        vpn_callback, resources.ROUTER_INTERFACE, events.BEFORE_DELETE)
+        vpn_router_gateway_callback, resources.ROUTER_INTERFACE,
+        events.BEFORE_DELETE)
     registry.subscribe(
         migration_callback, resources.ROUTER, events.BEFORE_UPDATE)
     registry.subscribe(