OF plugin classes must have a strict dependency on Connection Service
ISSUE:
In scaled setup we see NPE in OF protocol plugin code as switches connect before the IPluginOUConnectionService reference is set
CHANGE:
- Have OF proto plugin Activator express a required dependency on IPluginOUConnectionService for the interested classes
- Removed stale unused conenction mgr related code from OF plugin classes
Change-Id: If8aa7239d5be0c1c206c3b4d42bfcbbe029b4588
Signed-off-by: Alessandro Boch <aboch@cisco.com>