Revert distutils changes done in r63248.

As explained by Marc-Andre Lemburg, distutils needs to stay
backward-compatible. Therefore, it should use the old ConfigParser
module name.
diff --git a/Lib/distutils/dist.py b/Lib/distutils/dist.py
index e4ab336..0b13c1e 100644
--- a/Lib/distutils/dist.py
+++ b/Lib/distutils/dist.py
@@ -359,7 +359,7 @@
 
     def parse_config_files (self, filenames=None):
 
-        from configparser import ConfigParser
+        from ConfigParser import ConfigParser
 
         if filenames is None:
             filenames = self.find_config_files()