Issue #4471: Properly shutdown socket in IMAP.shutdown().  Patch by
Lorenzo M. Catucci.
diff --git a/Misc/ACKS b/Misc/ACKS
index 361cdf9..3cb3a29 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -130,6 +130,7 @@
 Brett Cannon
 Mike Carlton
 Terry Carroll
+Lorenzo M. Catucci
 Donn Cave
 Charles Cazabon
 Per Cederqvist