Remove "insecure" in token-based authentication.
Remove "insecure" in token-based authentication.

Currently, in mistralclient we are using insecure parameter for
token-based authentication but insecure parameter shouldnot be used
in token-based authentication.

Change-Id: Ibf2de27b692e7a244795c210d586339953983329
Closes-Bug: #1718199

openstack/python-mistralclient,StackStorm/python-mistralclient,openstack/python-mistralclient,StackStorm/python-mistralclient