Fix --exlude typo in tox.ini

This commit corrects a typo recently introduced to update our language to
be more inclusive:

  https://review.opendev.org/c/openstack/tempest/+/768583

This typo is causing failures in neutron tempest runs.

Change-Id: I1d867dc0a1641a3c364984c5a91e301a2d938d01
1 file changed