openstack-full: Remove package neutron-plugins-openvswitch

In @zigo's packages, neutron-common contains all the plugins.
So neutron-plugins-openvswitch doesn't exist anymore.
In the code it has been replaced by neutron-common itself.
openstack-full: Do not recompile the openvswitch kernel module

Since Ubuntu 14.04 LTS includes Open vSwitch 2.0.1 there is no need
to recompile the openvswitch kernel module.