Add neutron-rootwrap-daemon to neutron_sudoers

There is no way to use neutron-rootwrap-daemon to improve Neutron rootwrap performance at scale with the current Neutron images.

Using neutron-rootwrap on huge environment could have a performance impact on many actions and be the root cause of failure during instance creation.

Operators should have the choice:
  - neutron-rootwrap
  - neutron-rootwrap-daemon

Discussion on this thread: http://lists.openstack.org/pipermail/openstack-operators/2018-May/015267.html

Without the change in neutron_sudoers we got this error:

2018-12-14 02:31:23.414 8 DEBUG neutron.agent.linux.utils [-] Running command (rootwrap daemon): ['ovs-vsctl', '--timeout=60', '--oneline', '--format=json', '--', '--may-exist', 'add-br', 'br-int', '--', 'set', 'Bridge', 'br-int', 'datapath_type=system', '--', 'add', 'Bridge', 'br-int', 'protocols', 'OpenFlow10', '--', 'set', 'Bridge', 'br-int', 'other_config:mac-table-size=50000'] execute_rootwrap_daemon /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/agent/linux/utils.py:103
2018-12-14 02:31:23.866 8 DEBUG oslo_rootwrap.client [-] Popen for ['sudo', 'neutron-rootwrap-daemon', '/etc/neutron/rootwrap.conf'] command has been instantiated _initialize /var/lib/kolla/venv/local/lib/python2.7/site-packages/oslo_rootwrap/client.py:73
2018-12-14 02:31:23.870 8 ERROR neutron.agent.linux.utils [-] Rootwrap error running command: ['ovs-vsctl', '--timeout=60', '--oneline', '--format=json', '--', '--may-exist', 'add-br', 'br-int', '--', 'set', 'Bridge', 'br-int', 'datapath_type=system', '--', 'add', 'Bridge', 'br-int', 'protocols', 'OpenFlow10', '--', 'set', 'Bridge', 'br-int', 'other_config:mac-table-size=50000']: Exception: Failed to spawn rootwrap process.
2018-12-14 02:31:23.871 8 ERROR neutron.agent.ovsdb.impl_vsctl [-] Unable to execute ['ovs-vsctl', '--timeout=60', '--oneline', '--format=json', '--', '--may-exist', 'add-br', 'br-int', '--', 'set', 'Bridge', 'br-int', 'datapath_type=system', '--', 'add', 'Bridge', 'br-int', 'protocols', 'OpenFlow10', '--', 'set', 'Bridge', 'br-int', 'other_config:mac-table-size=50000']. Exception: Failed to spawn rootwrap process.
stderr:
sudo: no tty present and no askpass program specified