Limit the socket buffer size to 64k for all sessions. Long time ago

Limit the socket buffer size to 64k for all sessions. Long time ago
setting the size to 64k was increasing the size but now auto-scaling
could grow the buffer size much more. The origianl idea was that sessions
without protection had a small window size to make window attacks
harder. This problem was fixed long time ago and is no longer relevant.
Limiting the buffer size to a reasonable size ensures that not too many
updates end up queued in the TCP stack.
OK benno@ (some time ago)