Update setup.sh for jupyter kernels

[heather999]

As described on Confluence: https://confluence.slac.stanford.edu/display/LSSTDESC/Using+Jupyter+at+NERSC#UsingJupyteratNERSC-setup
after running source /global/common/software/lsst/common/miniconda/kernels/setup.sh
it is suggested to run jupyter kernelspec list
This fails because the desc-python base environment is not activated, which isn't necessary to set up the kernels.. but then you can't run this check.