add_router_interface should check ip overwrapping

[Nachi Ueno]

Duplication of subnet is checked but duplication of ip cider is not checked.

[dan wendlandt (danwent)]

Hi Ishii-san, thanks for fixing this. Great to have you contributing to Quantum :)

[Hisaharu Ishii (ishii-hisaharu)]

Hi dan-san, I'm so happy to contribute to Quantum :)
I appreciate if you would review my patch after I will put it.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/12537

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/12537
Committed: http://github.com/openstack/quantum/commit/5c5aadd2a1cc404acf1240f5273cce3c6d7d575a
Submitter: Jenkins
Branch: master

commit 5c5aadd2a1cc404acf1240f5273cce3c6d7d575a
Author: Hisaharu Ishii <email address hidden>
Date: Thu Sep 6 17:32:56 2012 -0700

    check subnet overlapping when adding interface to router

    Fixes bug 1046061

    Add logic in _check_for_dup_router_subnet to check subnets are not overlapped.
    Add testcase test_router_add_interface_overlapped_cidr.

    Change-Id: I71b6cce07273686cc5e4636ce640b7201ce00b32