MINOR: ssl: allow to change the client-sigalgs on server lines

This patch introduces the "client-sigalgs" keyword for the server line,
which allows to configure the list of server signature algorithms
negociated during the handshake. Also available as
"ssl-default-server-client-sigalgs" in the global section.

include/haproxy/server-t.h

@@ -393,6 +393,7 @@ struct server {
 		char *crl_file;			/* CRLfile to use on verify */
 		char *client_crt;		/* client certificate to send */
 		char *sigalgs;			/* Signature algorithms */
+		char *client_sigalgs;           /* Client Signature algorithms */
 		struct sample_expr *sni;        /* sample expression for SNI */
 		char *npn_str;                  /* NPN protocol string */
 		int npn_len;                    /* NPN protocol string length */

include/haproxy/ssl_sock-t.h

@@ -285,6 +285,7 @@ struct global_ssl {
 #endif
 #if defined(SSL_CTX_set1_sigalgs_list)
 	char *listen_default_client_sigalgs;
+	char *connect_default_client_sigalgs;
 #endif
 	int listen_default_ssloptions;
 	int connect_default_ssloptions;