Fix bug in code generator which prevented it from generating code

Signed-off-by: Andrew Keesler <akeesler@vmware.com>

hack/module.sh

@@ -59,10 +59,9 @@ function with_modules() {
   for mod_file in $(find . -maxdepth 4 -name go.mod | sort); do
     mod_dir="$(dirname "${mod_file}")"
     (
-      export MOD_DIR
       echo "=> "
       echo "   cd ${mod_dir} && ${cmd}"
-      cd "${mod_dir}" && MOD_DIR="$(pwd)" && ${cmd}
+      cd "${mod_dir}" && ${cmd}
     )
   done
   popd