Log os-brick privileged commands in Nova (OSP13 - OSP16)

Since OSP13 nova cpu logs no longer show privileged commands run by os-brick even when debug is enabled in nova it may be insufficient to debug cases.

This was changed to limit the amount of sensitive information that is presented in the nova logs, unfortunately for debugging attach and detach issues related to os-brick those logs are really necessary, as current os-brick logging is cou...