use embedded URLs for hyperlinks in the README

This switches all hyperlinks to embedded links, from a much more fragile
indirect & anonymous approach (which happens to be completely broken
on Github).

Change-Id: I92700068c7d65b50c76ce6931bff3ebab4844a49
Closes-Bug: 1335968
Use keystoneclient.exceptions

keystoneclient.apiclient.exceptions is deprecated.
Instead keystoneclient.exceptions should be used.

Change-Id: I546defeac5c2a1f4d3e68885e45019a6a6ecb027
Redact tokens in request headers

Tokens shouldn't be logged since a token could be gathered from a
log file and used. The client was logging the X-Auth-Token and
X-Subject-Token request headers. With this change, the X-Auth-Token
and X-Subject-Token are shown as "TOKEN_REDACTED".

Also, the "Authentication" header is also redacted.

This is for security hardening.

SecurityImpact

Closes-Bug: #1004114
Closes-Bug: #1327019

Change-Id: I1edc3821ed028471102cc9b95eb9f3b54c9e2778
Use config fixture from oslo.config

With the release of oslo.config 1.4.0.0a1, oslo.config
contains the config fixture. python-keystoneclient was using
the config fixture in oslo-incubator's fixture module. With
this change python-keystoneclient is using the config fixture
in oslo.config

Change-Id: Id03efdfbe8893c48a9ad65f0cf59e1dbae03dc47
Config fixture from oslo-incubator is not used.

Keystoneclient doesn't use the config fixture, so remove it from
openstack-common.conf and re-sync to remove it.

Change-Id: I9cf85a0bbbceb4c36e6ec968b19f34bb0716be95
Merge "use embedded URLs for hyperlinks in the README"
Merge "Redact tokens in request headers"
Merge "Use keystoneclient.exceptions"