Incorrect use of get_gateway retval in DeviceManager

[Carl Baldwin]

My patch to #1181378 did not properly handle the return value from get_gateway. I'll fix it with a patch coming right up.

[Carl Baldwin (carl-baldwin)]

This bug is not terribly urgent. The code in DeviceManager still works but it ends up calling add_gateway more often than necessary.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/34833

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/34833
Committed: http://github.com/openstack/quantum/commit/21fd100a98c152086193607cd311c2ee03b82643
Submitter: Jenkins
Branch: master

commit 21fd100a98c152086193607cd311c2ee03b82643
Author: Carl Baldwin <email address hidden>
Date: Fri Jun 28 03:07:00 2013 +0000

    Update code to properly use dict returned from get_gateway.

    Calling get_gateway was a late addition to my code to add a default
    route in the DHCP namespace. The code did not properly handle the
    dict returned from that method. This changes it to properly extract
    the 'gateway' attribute from the dict.

    Change-Id: I9823a31feee7ab333c277fc6e78f366408393155
    Fixes: Bug #1195543