[PATCH 1 of 2] import-checker: force 'ctype.util' to stdlib module

[Matt Harbison]

# HG changeset patch
# User Matt Harbison <matt_harbison at yahoo.com>
# Date 1450838860 18000
#      Tue Dec 22 21:47:40 2015 -0500
# Node ID 8f83787abed009b037f0c94cb42207b34c9c87b8
# Parent  fe376159a58d9b3d748b669ac011b0eed0346fea
import-checker: force 'ctype.util' to stdlib module

Not having this caused warnings on Windows:

  mercurial/pure/osutil.py:12: stdlib import follows local import: os
  mercurial/pure/osutil.py:13: stdlib import follows local import: socket
  mercurial/pure/osutil.py:14: stdlib import follows local import: stat
  mercurial/pure/osutil.py:15: stdlib import follows local import: sys

diff --git a/contrib/import-checker.py b/contrib/import-checker.py
--- a/contrib/import-checker.py
+++ b/contrib/import-checker.py
@@ -180,7 +180,7 @@
     for m in ['msvcrt', '_winreg']:
         yield m
     # These get missed too
-    for m in 'ctypes', 'email', 'multiprocessing':
+    for m in 'ctypes', 'ctypes.util', 'email', 'multiprocessing':
         yield m
     yield 'builtins' # python3 only
     for m in 'fcntl', 'grp', 'pwd', 'termios':  # Unix only