.circleci: Set +u for all conda install commands (#50505)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/50505
Even with +u set for the the conda install it still seems to fail out
with an unbound variable error. Let's try and give it a default value
instead.
Signed-off-by: Eli Uriegas <eliuriegas@fb.com>
Test Plan: Imported from OSS
Reviewed By: pbelevich
Differential Revision: D25913692
Pulled By: seemethere
fbshipit-source-id: 4b898f56bff25c7523f10b4933ea6cd17a57df80
