Use top_bound_segment in delete_network_postcommit

[Romil Gupta]

We should use top_bound_segment instead of bound_segment in delete_network_postcommit method.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/liberty
Review: https://review.openstack.org/248825

[OpenStack Infra (hudson-openstack)]

Change abandoned by Romil Gupta (<email address hidden>) on branch: stable/liberty
Review: https://review.openstack.org/248764
Reason: Cherry-picked correctly, https://review.openstack.org/#/c/248825/.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/248825
Committed: https://git.openstack.org/cgit/openstack/networking-vsphere/commit/?id=ddf58ab1f22ce71670e18d538ed1b01244bf1d61
Submitter: Jenkins
Branch: stable/liberty

commit ddf58ab1f22ce71670e18d538ed1b01244bf1d61
Author: Romil Gupta <email address hidden>
Date: Sun Nov 1 21:57:53 2015 -0800

    Use top_bound_segment in delete_network_postcommit

    (cherry picked from commit 839acb7d331bc3a8bf19dfb10950490f899a7412)

    Closes-Bug: #1519021

    Conflicts:
     networking_vsphere/tests/unit/ml2/test_ovsvapp_mech_driver.py

    Change-Id: Iac5cd2db2048ca3dc5b77af9aa157006cb359962