Revert "blockcheck: enable ECN in windows"

This reverts commit 4d35d8d1ec.

blockcheck.sh

@@ -400,9 +400,6 @@ check_system()
 			# ts fooling requires timestamps. they are disabled by default in windows.
 			echo enabling tcp timestamps
 			netsh interface tcp set global timestamps=enabled >/dev/null
-			# they may not enable additional fake protection if ECN is enabled
-			echo enabling ECN
-			netsh int tcp set global ecn=enabled >/dev/null
 			;;
 		*)
 			echo $UNAME not supported