Namespace is not removed when router is deleted.

[Amit K]

When the router is deleted, the destroy namespace (_destroy_router_namespace) is called but the namespace still exists. The namespace must actually be deleted calling either the netns delete or garbage_collect_namespace.

[Mark McClain (markmcclain)]

This is a known issue from the Folsom release. Namespaces deletion would fail randomly when they were removed immediately after use. It is recommended to run quantum-netns-cleanup periodically. This will also the resources to settle into a state that deletion is likely to succeed. Some of the available packages should install this periodic job for you.