SSL_SESSION_up_ref is actually present from OpenSSL 1.1.0 but its presence
seems to break tests in IO-Socket-SSL with OpenSSL 1.1.0h in Fedora 26.

--- SSLeay.xs
+++ SSLeay.xs
@@ -2682,7 +2682,7 @@ d2i_SSL_SESSION(pv)
     OUTPUT:
 	RETVAL
 
-#if (OPENSSL_VERSION_NUMBER >= 0x10100004L && !defined(LIBRESSL_VERSION_NUMBER)) || (LIBRESSL_VERSION_NUMBER >= 0x2070000fL)
+#if (OPENSSL_VERSION_NUMBER >= 0x10101000L && !defined(LIBRESSL_VERSION_NUMBER)) || (LIBRESSL_VERSION_NUMBER >= 0x2070000fL)
 
 int
 SSL_SESSION_up_ref(sess)