Remove incorrect imports rationale comment in http.server (#128278)

Remove reference to gethostbyaddr(), because it's not actually used within this code.

Lib/http/server.py

@@ -99,7 +99,7 @@
 import posixpath
 import select
 import shutil
-import socket # For gethostbyaddr()
+import socket
 import socketserver
 import sys
 import time