
training-labs repo is retired now[1], this commit removes the reference of it from openstack manual. Depends-On: https://review.opendev.org/c/openstack/training-labs/+/817505 [1] http://lists.openstack.org/pipermail/openstack-discuss/2021-October/025586.html Change-Id: Id5ff713810ab07780dc14048c056341806dfc4c2