Merge pull request #3117 from xavfernandez/fix_split_leading_dir

Fix split_leading_dir, no need to cast to str

Author: xavfernandez

pip/utils/__init__.py

@@ -221,7 +221,6 @@ def file_contents(filename):
 
 
 def split_leading_dir(path):
-    path = str(path)
     path = path.lstrip('/').lstrip('\\')
     if '/' in path and (('\\' in path and path.find('/') < path.find('\\')) or
                         '\\' not in path):