Set channels on condarc. Fix conda version on clone.
This PR solves two issues:
-
Users prefer
conda-forgeas primary channel source. Thus we modify the globalcondarcto specify so. - Since we do a conda clone and then a
conda install conda, if we have cached a newer version of conda we install that newer version. Here we fix this to maintain reproducibility. A user can always update conda on the clone.
This work is part of https://phabricator.wikimedia.org/T321088.