make configure script look for correct Szip library
see also https://www.unidata.ucar.edu/support/help/MailArchives/netcdf/msg10433.html

author: Kenneth Hoste (HPC-UGent)

--- netcdf-4.1.3/configure.orig	2017-02-28 17:55:46.681729087 +0100
+++ netcdf-4.1.3/configure	2017-02-28 17:55:52.391876458 +0100
@@ -27142,7 +27142,7 @@
   return 0;
 }
 _ACEOF
-for ac_lib in '' szip; do
+for ac_lib in '' sz; do
   if test -z "$ac_lib"; then
     ac_res="none required"
   else
