delete_subnet in ml2 plugin makes 2 calls to get the subnet

[Rossella Sblendido]

delete_subnet makes 2 calls to get the same subnet:

one here: https://github.com/openstack/neutron/blob/master/neutron/plugins/ml2/plugin.py#L711
the second here: https://github.com/openstack/neutron/blob/master/neutron/plugins/ml2/plugin.py#L734

Only one call is needed

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/119399

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/119399
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=6fffe3bf841667e9a303351cf6dc05e6643b9291
Submitter: Jenkins
Branch: master

commit 6fffe3bf841667e9a303351cf6dc05e6643b9291
Author: Sam Betts <email address hidden>
Date: Fri Sep 5 16:16:01 2014 +0100

    Remove second call to get_subnets in delete_subnet

    delete_subnet made calls to both get_subnet and _get_subnet,
    get_subnet uses _get_subnet so multiple database requests were being
    made, this patch removes the call to get_subnet and directly calls
    _make_subnet_dict using the result of _get_subnet

    Change-Id: I9982821dbb9447e35a4b6e50bc5ad31cec417ca5
    Closes-Bug: 1366056