BUG/MINOR: tcpcheck: Disable QUICKACK for default tcp-check (with no rule)

The commit 871dd8211 ("BUG/MINOR: tcpcheck: Disable QUICKACK only if data
should be sent after connect") introduced a regression. It removes the test
on the next rule to be able to disable TCP_QUICKACK when only a connect is
performed (so no next rule).

This patch must be backported as far as 2.2.
diff --git a/src/tcpcheck.c b/src/tcpcheck.c
index 7e7627a..e597cf8 100644
--- a/src/tcpcheck.c
+++ b/src/tcpcheck.c
@@ -1187,8 +1187,10 @@
 	if (proto && proto->connect) {
 		int flags = 0;
 
+		if (!next)
+			flags |= CONNECT_DELACK_ALWAYS;
 		if (connect->options & TCPCHK_OPT_HAS_DATA)
-			flags = (CONNECT_HAS_DATA|CONNECT_DELACK_ALWAYS);
+			flags |= (CONNECT_HAS_DATA|CONNECT_DELACK_ALWAYS);
 		status = proto->connect(conn, flags);
 	}