Update deprecated Glance CLI

Since this patch has been merged in python-glanceclient 0.14.1:
https://github.com/openstack/python-glanceclient/commit/1dfce5301c5d7cd456c98629a007917120637c8a

We have to update the way to call Glance Client.
This patch updates for glance image-list, image-show and the way to get
a token, and also the way the glance command output is parsed.

Change-Id: If3e1e42b1245dd064fa00e07037535afc9caa04c