remove NERSC_HOST in setting target

Open Chun Hong Yoon requested to merge cgpu_build into development

Main motivation here is to not set SPINIFEL_TARGET variable on cori gpu. $NERSC_HOST is not needed, and produces wrong target if the user forgets to set SPINIFEL_TARGET.

If SPINIFEL_TARGET is needed on other machines we can keep it, otherwise we could remove this variable too.

Merge request reports