MINOR: ssl: show methods supported by openssl

TLS v1.3 incoming, SSLv3 will disappears: it could be useful to list
all methods supported by haproxy/openssl (with -vvv).
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index 63c0f79..5014e70 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -7538,7 +7538,7 @@
 	ptr = NULL;
 	memprintf(&ptr, "Built with OpenSSL version : "
 #ifdef OPENSSL_IS_BORINGSSL
-		"BoringSSL\n");
+		"BoringSSL");
 #else /* OPENSSL_IS_BORINGSSL */
 	        OPENSSL_VERSION_TEXT
 		"\nRunning on OpenSSL version : %s%s",
@@ -7567,6 +7567,24 @@
 #endif
 	       "", ptr);
 
+	memprintf(&ptr, "%s\nOpenSSL library supports : "
+#if SSL_OP_NO_SSLv3
+		  "SSLv3 "
+#endif
+#if SSL_OP_NO_TLSv1
+		  "TLSv1.0 "
+#endif
+#if SSL_OP_NO_TLSv1_1
+		  "TLSv1.1 "
+#endif
+#if SSL_OP_NO_TLSv1_2
+		  "TLSv1.2 "
+#endif
+#if SSL_OP_NO_TLSv1_3
+		  "TLSv1.3"
+#endif
+	       "", ptr);
+
 	hap_register_build_opts(ptr, 1);
 
 	global.ssl_session_max_cost   = SSL_SESSION_MAX_COST;