nova wrongly attaches different network with similar name

[Kaustubh Phatak]

Description
===========
Setup: Nova VMware driver
If there are one than one network with substring matching name (Test_Net and Test_Net_10.0.0.0) on vCenter, Nova attaches Test_Net_10.0.0.0 instead of Test_Net
If VM has multiple networks like both in above case, it will attach Test_Net_10.0.0.0 multiple times. This only happens in case of VMware DVPortGroup

Steps to reproduce
==================
* Setup Multiple Port Groups in VMware DVSwitch Environment (Test_Net and Test_Net_10.0.0.0)
* Create instance with Test_Net
* Verify that on vSphere, it will have Test_Net_10.0.0.0 network adaptor

Expected result
===============
Instance should have correct network adaptor as in the request

Actual result
=============
Instance will have network adaptor name not matching to the one in original request

Environment
===========
1. Exact version of OpenStack you are running. See the following
  list for all releases: http://docs.openstack.org/releases/

   Verified on Newton, Okata, Pike

2. Which hypervisor did you use?
   vSphere 6.0 with ESXi 6.0

3. Which networking type did you use?
   nova-network

[Takashi Natsume (natsume-takashi)]

Set the status to "In-progress" because this report has an assignee.