Update ovssfc to use latest mdsal broker APIs

First pass: supported SFF Data Listener
Second pass:
- Added Abstract Data Listener to support more listeners
- Added SFC and SFP listeners.

Change-Id: Ia8c8d11ea0712e4654a20b8c4badb011feeb8bcb
Signed-off-by: Sam Hague <shague@redhat.com>
Merge "Update ovssfc to use latest mdsal broker APIs"