Not fail tasks by fail of pushing log file

[navis]

It's too harsh to fail the task by failure of pushing log file.

      log.warn("Unable to create task log dir[%s]", directory.getAbsolutePath());
      File tempFile = File.createTempFile(taskid, ".log");
      Files.copy(file, tempFile);
      log.info("Wrote task log to temporary file: %s", tempFile);