datapath-windows: Calling OvsAddPidInstance and OvsDelPidInstance

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