Add oslo.utils and oslo.i18n libs to requirements

This commit adds two oslo libs, that are common for all
OpenStack projects:
- oslo.i18n
- oslo.utils

1) oslo.i18n is used for translation and is dependency of
oslo.utils

2) oslo.utils lib contains following modules from incubator:
- encodeutils
- excutils
- importutils
- netutils
- strutils
- timeutils
- units

Change-Id: I461627f14204abb1233c83dea54abfff0bf84d7c
Merge "Add oslo.utils and oslo.i18n libs to requirements"