ospf6d: Adding the initialization check in ospfv3_clean()
This is to avoid a crash triggered by process termination
when ospf6d daemon is running and 'router ospf6' config has not been done yet.
Signed-off-by: Vipin Kumar <vipin@cumulusnetworks.com>
Reviewed-by: Daniel Walton <dwalton@cumulusnetworks.com>