Issue #17047: remove doubled words added in 3.3
as reported by Serhiy Storchaka and Matthew Barnett.
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 4198207..a6f8c5a 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -3609,7 +3609,7 @@
the next header, it checks its (uninitialized) cmsg_len
member to see if the "message" fits in the buffer, and
returns NULL if it doesn't. Zero-filling the buffer
- ensures that that doesn't happen. */
+ ensures that this doesn't happen. */
memset(controlbuf, 0, controllen);
for (i = 0; i < ncmsgbufs; i++) {