ml2 plugin wrongly calls _filter_nets_l3 from get_networks

[Isaku Yamahata]

The commit of 0156ec175cc047826b211727d43d5d14a3e1f2d2, change-id of I47e01a11afaf6e6bcf06da7bd713fd39b05600ff which fixes bug 1132849 removed the call of _filter_nets_l3 methods.
But the fix missed ml2 plugin somehow.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/129149

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/129149
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=9436cbdfb2c0d113517bc6108ded7d0397a096cb
Submitter: Jenkins
Branch: master

commit 9436cbdfb2c0d113517bc6108ded7d0397a096cb
Author: Isaku Yamahata <email address hidden>
Date: Fri Oct 17 15:35:44 2014 +0900

    ml2: remove stale _filter_nets_l3 in get_networks

    The commit of 0156ec175cc047826b211727d43d5d14a3e1f2d2
    change-id of I47e01a11afaf6e6bcf06da7bd713fd39b05600ff
    which fixes bug 1132849 removed the call of _filter_nets_l3 methods.
    But somehow the fix missed ml2 plugin.
    This patch fixes ml2 plugin and removes the unused mothod.

    Change-Id: I4d13223c170fd6777773970e0d22a191b98dd5ee
    Closes-Bug: #1382360

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: neutron-pecan
Review: https://review.openstack.org/185072