Switch to stein tags
Switch to stein tags

RDO is moving to stein tags in [1], so we need to adapt
DLRN builders configuration.

[1] https://review.rdoproject.org/r/#/c/15570/

Change-Id: Ic71ecb2c0b3d2b6949abe1f68a5d9989c9133484
Depends-On: https://review.rdoproject.org/r/#/c/15570/

rdo-infra/puppet-dlrn,javierpena/puppet-delorean,javierpena/puppet-delorean,rdo-infra/puppet-dlrn,rdo-infra/puppet-dlrn,javierpena/puppet-delorean