Replace glance.client with python-glanceclient

The legacy glance client code is going to be removed soon, so
Tempest needs to stop using it. This patch updates Tempest to
use the shiny new python-glanceclient library.

This requires python-glanceclient 0.5.1+ to work.

Fixes bug 1048716

Change-Id: I6e0773644ed1e4e19448a5899a71ee2ed5d36f82
3 files changed