Auth_token middleware is expected to be configured by use of
oslo.config. Paste is really only mainted for swift. However paste
overrides the values provided in oslo.config so for anyone using
default barbican paste files and configuring auth_token middleware via
oslo.config they will have unexpected config overrides from the barbian
defaults.
Change-Id: I6bc49c4b62167410eaa70432f73abab2e829dc39
700d16fa9e