Fix missing stacktraces in logs, caused by slf4j-api version 1.8.x
Fix missing stacktraces in logs, caused by slf4j-api version 1.8.x

telstra/open-kilda,telstra/open-kilda,telstra/open-kilda,telstra/open-kilda,telstra/open-kilda,telstra/open-kilda,telstra/open-kilda