Issue #16719: Get rid of WindowsError. Use OSError instead

Patch by Serhiy Storchaka.
diff --git a/PC/VC6/build_ssl.py b/PC/VC6/build_ssl.py
index 95af084..89554b8 100644
--- a/PC/VC6/build_ssl.py
+++ b/PC/VC6/build_ssl.py
@@ -66,7 +66,7 @@
             # note: do not abspath s; the build will fail if any
             # higher up directory name has spaces in it.
             fnames = os.listdir(s)
-        except os.error:
+        except OSError:
             fnames = []
         for fname in fnames:
             fqn = os.path.join(s, fname)