Fixed invalid variable name.

generate.py

@@ -101,7 +101,7 @@ def main():
         # Add header
         # Add header
         print('Create header file…', file=sys.stderr)
         print('Create header file…', file=sys.stderr)
         header_path = os.path.join(experiment_dir, 'defines.h')
         header_path = os.path.join(experiment_dir, 'defines.h')
-        create_header(args.header, experiment, header_dir)
+        create_header(args.header, experiment, header_path)
 
 
         # Add makefile & c++ file
         # Add makefile & c++ file
         print('Adding Makefile…', file=sys.stderr)
         print('Adding Makefile…', file=sys.stderr)