Switch fileutils to use python logging

oslo.concurrency code needs fileutils from oslo-incubator.
fileutils needs the common copy of log.py. What happens when we
import oslo.concurrency into nova, we end up with duplicate
options for default_log_levels. So to unravel the knots,
we switch fileutils over to python logging and hence remove
the need for common copy of log.py in oslo.concurrency.

Change-Id: Ida7ff3418db7c2a0a5e8b827e1c277533812b8ed
Merge "Switch fileutils to use python logging"
Updated from global requirements

Change-Id: I4cb3e687308ac42608c6f4ee1f2c90671e07c34a
Updated from global requirements

Change-Id: I2521bd0e356c2632444ccdfbf940243c2ff4d323