Allow SHA-1 in SSL renegotiation tests

In the TLS test client, allow SHA-1 as a signature hash algorithm.
Without this, the renegotation tests failed.

A previous commit had allowed SHA-1 via the certificate profile but
that only applied before the initial negotiation which includes the
signature_algorithms extension.
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 7da91e6..fcc7f5f 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -2134,8 +2134,8 @@
      */
     if( mbedtls_ssl_check_sig_hash( ssl, *md_alg ) != 0 )
     {
-        MBEDTLS_SSL_DEBUG_MSG( 1, ( "server used HashAlgorithm "
-                                    "that was not offered" ) );
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "server used HashAlgorithm %d that was not offered",
+                                    *(p)[0] ) );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
     }