Allow router_delete_namespaces and dhcp_delete_namespaces to be overridden

[Eric Zhou]

Need to allow router_delete_namespaces and dhcp_delete_namespaces to be overridden so that the namespaces can be removed when corresponding routers and networks are deleted.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/104059

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/104059
Committed: https://git.openstack.org/cgit/stackforge/cookbook-openstack-network/commit/?id=54ea878fea30d20fd9aa4d3343438797173c3029
Submitter: Jenkins
Branch: master

commit 54ea878fea30d20fd9aa4d3343438797173c3029
Author: ericzhou <email address hidden>
Date: Wed Jul 2 11:19:22 2014 +0800

    Allow namespaces to be removable.

    When network namespaces are used for dhcp and l3, we need to allow
    router_delete_namespaces and dhcp_delete_namespaces to be overridden so
    that the namespaces can be deleted.

    Change-Id: I8255f0a43ffd1100f971470208103503e9dd8229
    Closes-Bug: #1336613