* explicitly set --os-image-api-version 1
This is necessary because python-glanceclient 1.0.0 will use v2 when v2
is accessible.
* only extract subcommands from lastline of bash-completion output
This is necessary because 'glance bash-completion' outputs a
warning starting with python-glanceclient 1.0.0.
---snip---
WARNING: The client is falling back to v1 because the accessing to v2
failed. This behavior will be removed in future versions
---snap---
Change-Id: I936f5704e3badd4cb12d3d9c0753eb154bf594b2