According to OpenStack Guideline[1], logged string message should be interpolated by the logger. Also, upgraded hacking requirement, to enable H904 check. [1]: http://docs.openstack.org/developer/oslo.i18n/guidelines.html#adding-variables-to-log-messages Co-Authored-By: jiansong <jian.song@easystack.cn> Change-Id: I3f020b6bcb1b9bf6d18a3b4f738c13cccd1bbff8 Closes-Bug: #1596829