osutil: remove Python 2.4 errno conversion workaround

mercurial/pure/osutil.py

@@ -59,7 +59,6 b" if os.name != 'nt':"
     posixfile = open
 else:
     import ctypes, msvcrt
-    from errno import ESRCH, ENOENT
 
     _kernel32 = ctypes.windll.kernel32
 
@@ -99,14 +98,7 b' else:'
 
     def _raiseioerror(name):
         err = ctypes.WinError()
-        # For python 2.4, treat ESRCH as ENOENT like WindowsError does
-        # in python 2.5 or later.
-        # py24:           WindowsError(3, '').errno => 3
-        # py25 or later:  WindowsError(3, '').errno => 2
-        errno = err.errno
-        if errno == ESRCH:
-            errno = ENOENT
-        raise IOError(errno, '%s: %s' % (name, err.strerror))
+        raise IOError(err.errno, '%s: %s' % (name, err.strerror))
 
     class posixfile(object):
         '''a file object aiming for POSIX-like semantics