Delete the token and endpoint on expiry of token of client

This change will guarantee that clients using this module will
renew the session on token expiry. Currently this fact causes
the issues with Ceilometer client and its usage in the
ceilometer-alarm-evaluator.

Co-Authored-By: vaibhav_kale <vaibhav_kale@persistent.co.in> 
Related-Bug: #1357343
Change-Id: I10b8c4c9d6aa4ce74028e91cc5e8a85e47e6953b
Merge "Delete the token and endpoint on expiry of token of client"