Correct typos in using-sessions

Fixed typos in using-sessions.

Change-Id: Id931bfdb8eb8bf214ca538673e727c6bf1e06280
Doc cleanup, make concepts links

Rather than just mention the concepts, make each reference a link to
the concept's representation in the API.

Change-Id: I4dadca0395784eb43e5bbb3cfd65c56c8f56ed38
Remove warning about management token

Because keystoneclient tries to figure out a management_url in all
contexts, it means that any end-user who uses any python-*client from
OpenStack that is using python-keystoneclient will always get a warning
about not being able to get a management token. This is, however, not
something that they need warning about, since there is no expectation
they'll have one. It's distressing to see it as part of normal
operation.

So just remove the warning.

Change-Id: Ia103a53c09c00fc09cef5fb24be546fc1da0684a
Use oslo_debug_helper and remove our own version

With the latest version of oslotest, we can now take advantage
of a common oslo_debug_helper script.
We can now remove our own homebrewed version, minor changes to
tox.ini were needed.

Change-Id: I907f7203aefedc9b33c3dfbfecc9793e273a4a8f
Prevent AttributeError if no authorization

If you ask client if there is a service catalog when it is unauthorized
it tries to look up the service catalog on a None object. If the client
is unauthorized it should always return False as there cannot be a
service catalog.

Change-Id: I439f71e548b8230e7ce38d1a0e9d0d8f9b205d77
Closes-Bug: 1239219
Merge "Remove warning about management token"
Merge "Prevent AttributeError if no authorization"
Merge "Use oslo_debug_helper and remove our own version"
Merge "Doc cleanup, make concepts links"
Merge "Correct typos in using-sessions"