bpo-30022: Get rid of using EnvironmentError and IOError (except test… (#1051)

diff --git a/Lib/urllib/error.py b/Lib/urllib/error.py
index 851515b..8cd901f 100644
--- a/Lib/urllib/error.py
+++ b/Lib/urllib/error.py
@@ -19,7 +19,7 @@
 class URLError(OSError):
     # URLError is a sub-type of OSError, but it doesn't share any of
     # the implementation.  need to override __init__ and __str__.
-    # It sets self.args for compatibility with other EnvironmentError
+    # It sets self.args for compatibility with other OSError
     # subclasses, but args doesn't have the typical format with errno in
     # slot 0 and strerror in slot 1.  This may be better than nothing.
     def __init__(self, reason, filename=None):