Use oslo.i18n package and handle different versions properly in
glanceclient._i18n. The oslo namespace is being deprecated so imports
will be oslo_i18n going forward. For older versions of oslo.i18n though,
we will still be able to import i18n from oslo.
Change-Id: Id56d34ccf447dc6f7becafb74d6a30e8a1642030
Ian Cordasco