Add new library oslo.utils

Add the new library oslo.utils so projects can start adopting it.

In order to use oslo.utils in python-keystoneclient (and probably in
other clients), the requirement has to be in stable/havana otherwise
the check-tempest-dsvm-full-havana-* jobs fail with an error:

 'oslo.utils' is not a global requirement but it should be,something
 went wrong

Conflicts:

	global-requirements.txt

Closes-Bug: #1357652

Change-Id: I9e61adfac71f159e3a6aa77cbcbb26279dc42869
(cherry picked from commit 10d2dfd4511dd4c7ba9c50d302058c33d6b6b778)
(cherry picked from commit daef7ed90d043c918f4fe4c5b5ae606998bb3055)