Sync the 'fileutils' module from oslo-incubator

Sync the 'fileutils' module from oslo-incubator

The fileutils module hasn't been updated since
November of 2014.  We need to bring this module up
to date to support the namespace changes that have
been made.

Current HEAD in OSLO:
---------------------
commit e589dde0721a0a67e4030813e582afec6e70d042
Date:  Wed Feb 18 03:08:12 2015 +0000
Merge "Have a little fun with release notes"

Changes merged with this patch:
---------------------
ac17de97 - Use oslo_utils instead of deprecated oslo.utils
809080ed - Introduce fileutils ensure_dir creation mode parameter

Change-Id: I0bca3cc59126abed8ef736bf5e199857f681e5cd