Restore Python 2.3 compatibility and remove "with" usage.

Lib/distutils/core.py

@@ -218,8 +218,7 @@ def run_setup (script_name, script_args=None, stop_after="run"):
             sys.argv[0] = script_name
             if script_args is not None:
                 sys.argv[1:] = script_args
-            with open(script_name, 'r') as file:
-                exec file.read() in g, l
+            exec open(script_name, 'r').read() in g, l
         finally:
             sys.argv = save_argv
             _setup_stop_after = None