Better failure logging when handleMessage failes

[rscorer]

In eclipse/vert.x/src/main/java/io/vertx/core/eventbus/impl/HandlerRegistration.java in method deliver there is a catch block which could be improved slightly.

It has been advantageous to me to see the address of the message handler which has failed (for whatever reason)

    } catch (Exception e) {
      log.error("Failed to handleMessage ", e);
      metrics.endHandleMessage(metric, e);
      throw e;

      if (message != null) {
        log.error("Failed to handleMessage '" + message.address() + "'", e);
      } else {
        log.error("Failed to handleMessage ", e);
      }

So now if my event handler "service.releaseaccount" has a failure I am told so by name, which could be quite useful

[jan-zajic]

PR #1896. Null check is useless as message method called about 9 rows above.