neutron.manager ImportError: No module named vnc_api.vnc_api

How to Fox it
http://fosshelp.blogspot.in/2015/04/howto-opencontrail-install-cfgmcommon.html

===Error:===

2014-12-16 22:06:11.262 INFO neutron.manager [-] Loading Plugin: neutron_plugin_contrail.plugins.opencontrail.loadbalancer.plugin.LoadBalancerPlugin
2014-12-16 22:06:11.263 DEBUG stevedore.extension [-] found extension EntryPoint.parse('dummy = neutron.tests.unit.dummy_plugin:DummyServicePlugin')
 from (pid=49770) _load_plugins /usr/local/lib/python2.7/dist-packages/stevedore/extension.py:156
2014-12-16 22:06:11.263 DEBUG stevedore.extension [-] found extension EntryPoint.parse('firewall = neutron.services.firewall.fwaas_plugin:FirewallPl
ugin') from (pid=49770) _load_plugins /usr/local/lib/python2.7/dist-packages/stevedore/extension.py:156
2014-12-16 22:06:11.263 DEBUG stevedore.extension [-] found extension EntryPoint.parse('metering = neutron.services.metering.metering_plugin:Meterin
gPlugin') from (pid=49770) _load_plugins /usr/local/lib/python2.7/dist-packages/stevedore/extension.py:156
2014-12-16 22:06:11.263 DEBUG stevedore.extension [-] found extension EntryPoint.parse('router = neutron.services.l3_router.l3_router_plugin:L3Route
rPlugin') from (pid=49770) _load_plugins /usr/local/lib/python2.7/dist-packages/stevedore/extension.py:156
2014-12-16 22:06:11.263 DEBUG stevedore.extension [-] found extension EntryPoint.parse('vpnaas = neutron.services.vpn.plugin:VPNDriverPlugin') from
(pid=49770) _load_plugins /usr/local/lib/python2.7/dist-packages/stevedore/extension.py:156
2014-12-16 22:06:11.263 DEBUG stevedore.extension [-] found extension EntryPoint.parse('lbaas = neutron.services.loadbalancer.plugin:LoadBalancerPlu
gin') from (pid=49770) _load_plugins /usr/local/lib/python2.7/dist-packages/stevedore/extension.py:156
2014-12-16 22:06:11.271 ERROR neutron.manager [-] Error loading plugin by name, No 'neutron.service_plugins' driver found, looking for 'neutron_plug
in_contrail.plugins.opencontrail.loadbalancer.plugin.LoadBalancerPlugin'

2014-12-16 22:06:11.271 TRACE neutron.manager Traceback (most recent call last):
2014-12-16 22:06:11.271 TRACE neutron.manager   File "/opt/stack/neutron/neutron/manager.py", line 137, in _get_plugin_instance
2014-12-16 22:06:11.271 TRACE neutron.manager     plugin_class = importutils.import_class(plugin_provider)
2014-12-16 22:06:11.271 TRACE neutron.manager   File "/opt/stack/neutron/neutron/openstack/common/importutils.py", line 28, in import_class
2014-12-16 22:06:11.271 TRACE neutron.manager     __import__(mod_str)
2014-12-16 22:06:11.271 TRACE neutron.manager   File "/opt/stack/neutron/neutron_plugin_contrail/plugins/opencontrail/loadbalancer/plugin.py", line
4, in
2014-12-16 22:06:11.271 TRACE neutron.manager     from loadbalancer_db import LoadBalancerPluginDb
2014-12-16 22:06:11.271 TRACE neutron.manager   File "/opt/stack/neutron/neutron_plugin_contrail/plugins/opencontrail/loadbalancer/loadbalancer_db.p
y", line 14, in
2014-12-16 22:06:11.271 TRACE neutron.manager     from vnc_api.vnc_api import VncApi
2014-12-16 22:06:11.271 TRACE neutron.manager ImportError: No module named vnc_api.vnc_api
2014-12-16 22:06:11.271 TRACE neutron.manager
2014-12-16 22:06:11.272 ERROR neutron.manager [-] Error loading plugin by class, No module named vnc_api.vnc_api
2014-12-16 22:06:11.272 TRACE neutron.manager Traceback (most recent call last):
2014-12-16 22:06:11.272 TRACE neutron.manager   File "/opt/stack/neutron/neutron/manager.py", line 137, in _get_plugin_instance
2014-12-16 22:06:11.272 TRACE neutron.manager     plugin_class = importutils.import_class(plugin_provider)
2014-12-16 22:06:11.272 TRACE neutron.manager   File "/opt/stack/neutron/neutron/openstack/common/importutils.py", line 28, in import_class
2014-12-16 22:06:11.272 TRACE neutron.manager     __import__(mod_str)
2014-12-16 22:06:11.272 TRACE neutron.manager   File "/opt/stack/neutron/neutron_plugin_contrail/plugins/opencontrail/loadbalancer/plugin.py", line
4, in
2014-12-16 22:06:11.272 TRACE neutron.manager     from loadbalancer_db import LoadBalancerPluginDb
2014-12-16 22:06:11.272 TRACE neutron.manager   File "/opt/stack/neutron/neutron_plugin_contrail/plugins/opencontrail/loadbalancer/loadbalancer_db.p
y", line 14, in
2014-12-16 22:06:11.272 TRACE neutron.manager     from vnc_api.vnc_api import VncApi
2014-12-16 22:06:11.272 TRACE neutron.manager ImportError: No module named vnc_api.vnc_api
2014-12-16 22:06:11.272 TRACE neutron.manager