Adding of specific flow validation in of plugin

- An of 1.0 switch silently accepts a flowmod which
  match does not have proper hierarchy of fields set.
  It installs the flow discarding the incorrect fields.
  This would cause inconsistency between flows in hw
  and flows in sw. The application needs to be notified
  that the flow would not be accepted as is by the openflow
  switch.

Change-Id: If70a642f2835147856d3517ad82faef3e9bb1e2c
Signed-off-by: Alessandro Boch <aboch@cisco.com>