[MINOR] config: fix too large ssl-hello-check message.

As reported by Cyril Bonté and Hervé Commowick, the ssl-hello-check
should use sizeof()-1 and not sizeof() for the message length.
diff --git a/src/cfgparse.c b/src/cfgparse.c
index 4036e29..a30a887 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -4817,9 +4817,9 @@
 		}
 
 		if (curproxy->options & PR_O_SSL3_CHK) {
-			curproxy->check_len = sizeof(sslv3_client_hello_pkt);
-			curproxy->check_req = (char *)malloc(sizeof(sslv3_client_hello_pkt));
-			memcpy(curproxy->check_req, sslv3_client_hello_pkt, sizeof(sslv3_client_hello_pkt));
+			curproxy->check_len = sizeof(sslv3_client_hello_pkt) - 1;
+			curproxy->check_req = (char *)malloc(curproxy->check_len);
+			memcpy(curproxy->check_req, sslv3_client_hello_pkt, curproxy->check_len);
 		}
 
 		/* The small pools required for the capture lists */