Update error code from ssl_parse_signature_algorithm

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index fb33b54..558755d 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -2812,7 +2812,7 @@
     {
         MBEDTLS_SSL_DEBUG_MSG( 1,
             ( "server used unsupported SignatureAlgorithm %d", (*p)[1] ) );
-        return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
+        return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
     }
 
     /*