Fixed a missing exception (`WindowsError`) when using the rmtree error handler on non-Windows systems.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17247 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/utils/_os.py

@@ -3,6 +3,13 @@ import stat
 from os.path import join, normcase, normpath, abspath, isabs, sep
 from django.utils.encoding import force_unicode
 
+try:
+    WindowsError = WindowsError
+except NameError:
+    class WindowsError(Exception):
+        pass
+
+
 # Define our own abspath function that can handle joining
 # unicode paths to a current working directory that has non-ASCII
 # characters in it.  This isn't necessary on Windows since the
@@ -45,6 +52,7 @@ def safe_join(base, *paths):
                          'path component (%s)' % (final_path, base_path))
     return final_path
 
+
 def rmtree_errorhandler(func, path, exc_info):
     """
     On Windows, some files are read-only (e.g. in in .svn dirs), so when