Bug 716: Errors on controller shutdown

Bug 716: Errors on controller shutdown

    Fixed miscellaneous errors on shutdown:
        -  FlowProvider, GroupProvider and MeterProvider: all throw an
           UnsupportedOperationEx from their close methods with a TODO message.
           Implemented close to close the commitHandlerRegistration.

        - NetconfSSHServer: logs a socket closed exception due to closing the socket
          on shutdown. We can ignore this and not log the error (if 'up' is false).

        - RestconfProvider: NPE in stop method calling session.close.
          The 'session' member is never initialized or otherwise used so removed it.

        - RuntimeMappingModule and SchemaServiceImplSingletonModule:
          IllegalStateException from bundleContext.ungetService() call because the
          bundle has already been shutdown. Ignore ex as this can occur
          normally.

Need someone to commit this!

Change-Id: I31d9d6d66418dda7f5b73c2ad12bb251f3689643
Signed-off-by: tpantelis <tpanteli@brocade.com>