Fixing error where fetched files are sometimes deleted on exit

The purpose of this MR is to fix an error where sometimes fetched files are deleted on exit despite adding delete_on_exit=True. This fixes issue #255 (closed)

pesummary/core/fetch.py

@@ -158,7 +158,8 @@ def download_and_read_file(
             _tempfilestodel.append(new_name)
         return new_name
     data = read(new_name, **kwargs)
-    shutil.move(new_name, local)
+    if conf.delete_temporary_downloads_at_exit:
+        shutil.move(new_name, local)
     return data