Use devstack's new way of doing things

Recent commits in devstack introduce shinny new helper functions. Let's
use them.

run_process() introduced in Ia3843818014f7c6c7526ef3aa9676bbddb8a85ca

configure_auth_token_middleware() introduced in
I3b6727d5a3bdc0ca600d8faa23bc6db32bb32260

Change-Id: Id8c3f71c98c7582f6f0c5ef589396af741958484
Merge "Use devstack's new way of doing things"