Tempest is going to be pinned for stable/ussuri(depends on) which
need to modify run-tempest role to use the constraints set by
the devstack or any job.
Because of Tempest 26.1.0 and with stestr 2.5.1 or 3.0.1 (beacause of upper
constraints of stestr 2.5.1 in stable/train and 3.0.1 in stable/ussuri )
which does not have new args exclude-regex so let's fallback to old arg if
new arg is passed.
Change-Id: I89ae6bd5137e57cb6ec5bc3c9edecc29489bca94
Ghanshyam Mann
7aa3b21e89