Fix NameError in run-tests.py

Author: mitya57

run-tests.py

@@ -10,7 +10,7 @@
  if ext == config.get(tests.get_section(os.path.basename(root), config), 'input_ext'):
  tests.generate(root, config)
  else:
- print(file, 'does not have a valid file extension. Check config.')
+ print(sys.argv[2], 'does not have a valid file extension. Check config.')
  else:
  tests.generate_all()
 else: