Fix redundant setup of MODULEPATH in test script

Use `module use` command to update MODULEPATH rather directly setting
and exporting this environment variable.

Author: xdelaruelle

shpc/main/modules/templates/test.sh

@@ -7,7 +7,6 @@ set -e
 
 # This script assumes lmod is setup, and module on the path
 
-export MODULEPATH="{{ module_dir }}$:${MODULEPATH}"
 module use "{{ module_dir }}"
 
 printf "Testing load of {{ module_name }}:{{ version }}\n"