removed mbedtls_ssl_conf_sig_hashes and temporarily re-add sig_hashes

Signed-off-by: Ben Taylor <ben.taylor@linaro.org>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index aa850aa..de8f13b 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -1486,6 +1486,9 @@
 
 #if defined(MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED)
 
+#if !defined(MBEDTLS_DEPRECATED_REMOVED)
+    const int *MBEDTLS_PRIVATE(sig_hashes);         /*!< allowed signature hashes           */
+#endif
     const uint16_t *MBEDTLS_PRIVATE(sig_algs);      /*!< allowed signature algorithms       */
 #endif /* MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED */