add ref to tst_h_scalar

git-svn-id: https://sub.unidata.ucar.edu/netcdf/trunk@3292 2e3060e4-1ed8-cf1f-9cc2-9586e844a556
added tst_h_scalar test

git-svn-id: https://sub.unidata.ucar.edu/netcdf/trunk@3293 2e3060e4-1ed8-cf1f-9cc2-9586e844a556