datapath-windows: Add netlink command vport set

Signed-off-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Signed-off-by: Nithin Raju <nithin@vmware.com>
Acked-by: Ankur Sharma <ankursharma@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
datapath-windows: Fixes in OvsSetVportCmdHandler()

In this patch, we make a few simple fixes based on reviewing the code.
The code as such is not tested. We'll be hitting the code path soon
and might make more fixes at that time.

Signed-off-by: Nithin Raju <nithin@vmware.com>
Acked-by: Ankur Sharma <ankursharma@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>