util: move "default" makedir to posix.py

util: move "default" makedir to posix.py

makedir is already defined in win32.py, which gets imported into util.py
via windows.py if we are running on Windows

--- a/mercurial/posix.py	Thu Jul 21 15:52:08 2011 -0500
+++ b/mercurial/posix.py	Fri Jul 22 09:53:15 2011 +0200
@@ -325,3 +325,6 @@
     except ImportError:
         pass
     return 80
+
+def makedir(path, notindexed):
+    os.mkdir(path)

--- a/mercurial/util.py	Thu Jul 21 15:52:08 2011 -0500
+++ b/mercurial/util.py	Fri Jul 22 09:53:15 2011 +0200
@@ -390,9 +390,6 @@
 
     return check
 
-def makedir(path, notindexed):
-    os.mkdir(path)
-
 def unlinkpath(f):
     """unlink and remove the directory if it is empty"""
     os.unlink(f)