datapath-windows: fix OVS_VPORT_TYPE

datapath-windows: fix OVS_VPORT_TYPE

The windows ovs kernel uses an OVS_VPORT_TYPE enum that is incompatible with
the userspace counterpart (enum ovs_vport_type from openvswitch.h). We must use
the same enum type for the netlink communication to work properly.

This patch makes the fix: "typedef enum ovs_vport_type OVS_VPORT_TYPE" and
changes the afferent kernel driver code:
o) vport types synthetic and emulated turn to: netdev
o) vport type internal turns to: internal
o) vport type external truns to: netdev (plus, we hold a field in vport,
"isExternal"

Signed-off-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Acked-by: Nithin Raju <nithin@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>