Deprecation warnings

```
./neutron-ext-net-ksv3 --network-type flat \
>     -g 10.0.8.1 -c 10.0.8.0/24 \
>     -f 10.0.8.201:10.0.8.254 ext_net
/usr/lib/python2.7/dist-packages/keystoneauth1/adapter.py:179: UserWarning: Using keystoneclient sessions has been deprecated. Please update your software to use keystoneauth1.
  warnings.warn('Using keystoneclient sessions has been deprecated. '
```