help/config: remove outdated false claim about pywin32 stable

help/config: remove outdated false claim about pywin32

Since version 1.8 (released on 2011-03-01), Mercurial doesn't use pywin32 any
more. The old fallback mechanism to use C:\Mercurial\Mercurial.ini if pywin32 is
not installed was removed in 244772f67ac1.

--- a/mercurial/help/config.txt	Fri May 04 09:14:55 2012 -0700
+++ b/mercurial/help/config.txt	Sun May 06 10:36:32 2012 +0200
@@ -83,9 +83,7 @@
     keys contain PATH-like strings, every part of which must reference
     a ``Mercurial.ini`` file or be a directory where ``*.rc`` files will
     be read.  Mercurial checks each of these locations in the specified
-    order until one or more configuration files are detected.  If the
-    pywin32 extensions are not installed, Mercurial will only look for
-    site-wide configuration in ``C:\Mercurial\Mercurial.ini``.
+    order until one or more configuration files are detected.
 
 Syntax
 ------