Load SSL's error strings in hashlib.
Without ERR_load_crypto_strings() functions like ERR_lib_error_string() return NULL.
diff --git a/Modules/_hashopenssl.c b/Modules/_hashopenssl.c
index d715500..222e5ef 100644
--- a/Modules/_hashopenssl.c
+++ b/Modules/_hashopenssl.c
@@ -847,6 +847,7 @@
     PyObject *m, *openssl_md_meth_names;
 
     OpenSSL_add_all_digests();
+    ERR_load_crypto_strings();
 
     /* TODO build EVP_functions openssl_* entries dynamically based
      * on what hashes are supported rather than listing many