Move the test requirement for glanceclient to an installation
requirement, since the central pollster uses it.
Add an installation requirement for cinderclient, since there
is also a central pollster that needs it.
Change-Id: I01fcc7c1d69a02b6ebf62b2c851e0e862f3439d9
Signed-off-by: Doug Hellmann <doug.hellmann@dreamhost.com>