Updated openstack/openstack
Project: openstack/python-openstackclient  97d1bbdafddf2e3e9cf94b56df1349dc29e2a6b0

Create message variables for exceptions

Instead of inline messages, let's create variables instead, as
it's easier to find strings, and mark them for translation.

Change-Id: Ibbcfdbc59d12a0cb4af50f73043d3ff7f3c76f99