Cisco N1kv plugin to send subtype on network profile creation

Make sure that the cisco n1kv neutron plugin sends the sub_type too
when a overlay network profile is created

Change-Id: I37e63131039077fa80a28fe725c09f0307acc2ea
Closes-Bug: 1357125
(cherry picked from commit e6ffc08de72a21980cde38d1a716d429311f7819)