Fix path to module-specific base directory.
    
    - Previously, based directory related to modules was set by the
      TCAR_SCRIPTS_MODULES_BASEDIR variable not TCAR_MODULE_BASEDIR.
      Because module-specific environment make use of TCAR_MODULE_BASEDIR
      instead of TCAR_SCRIPTS_MODULES_BASEDIR the script failed to load
      module-specific related function. This update changes the variable
      name from TCAR_SCRIPT_MODULES_BASEDIR to TCAR_MODULES_BASEDIR.