SL-18837: Make NamedTempFile name template compatible with Python.

The recommended template uses hyphens; change to underscores to be valid
Python temp module names.

indra/test/namedtempfile.h

@@ -83,8 +83,9 @@ class NamedTempFile: public boost::noncopyable
     {
         // Create file in a temporary place.
         boost::filesystem::path tempname{ boost::filesystem::temp_directory_path() };
-        // unique_path() recommended model
-        tempname += stringize(pfx, "%%%%-%%%%-%%%%-%%%%", sfx);
+        // unique_path() recommended template, but with underscores instead of
+        // hyphens: some use cases involve temporary Python scripts
+        tempname += stringize(pfx, "%%%%_%%%%_%%%%_%%%%", sfx);
         mPath = boost::filesystem::unique_path(tempname);
         boost::filesystem::ofstream out{ mPath };