ofproto-dpif: Don't try to use dpif_probe_feature() with Windows datapath.

ofproto-dpif: Don't try to use dpif_probe_feature() with Windows datapath.

This patch disables features which are not currently supported in the
Windows datapath.

Unfortunately we have to do it in userspace because dpif_probe_feature is
not treated accordingly in the Windows datapath.  Fixing that is the
correct solution; this commit works around it for branch-2.4.

I opened the issue to track the feature for later implementations:
https://github.com/openvswitch/ovs-issues/issues/85

Signed-off-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Acked-by: Eitan Eliahu <eliahue@vmware.com>
Acked-by: Nithin Raju <nithin@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>