[3.12] gh-128731: Explicitly close socket on error in robotparser.RobotFileParser.read() (GH-128733) (GH-128756)

(cherry picked from commit 5e65a1acc0)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Lib/urllib/robotparser.py

@@ -65,6 +65,7 @@ def read(self):
                 self.disallow_all = True
             elif err.code >= 400 and err.code < 500:
                 self.allow_all = True
+            err.close()
         else:
             raw = f.read()
             self.parse(raw.decode("utf-8").splitlines())