Comment 1 for bug 1563495

That happens because X-Auth-Token header stored in request.Session entity.
The session was instantiated in http client initialization.
Honestly, I think keystone sessions is the right thing you need to use to instantiate glanceclient.
Right now you can several WA for the current approach:
1) Instantiate glanceclient when token expires
2) Instantiate httpclient when token expires
the third option is send self.auth_token each time somebody executes any action instead of storing it in session is also reasonable. I will try to propose a fix for that.