Fix build with LibreSSL 2.7 

LibreSSL 2.7 implemented OpenSSL 1.1 API

See also: https://reviews.freebsd.org/D14849#change-KhYbRXBMIBod

Cheers,
Bernard Spil (brnrd@FreeBSD.org)

[Retrieved (and backported) from:
https://sourceforge.net/p/trousers/bugs/234]
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

--- ./src/trspi/crypto/openssl/rsa.c.orig	2016-11-23 12:26:19 UTC
+++ ./src/trspi/crypto/openssl/rsa.c
@@ -38,7 +38,7 @@
 #define DEBUG_print_openssl_errors()
 #endif
 
-#if (OPENSSL_VERSION_NUMBER < 0x10100001L) || defined(LIBRESSL_VERSION_NUMBER)
+#if (OPENSSL_VERSION_NUMBER < 0x10100001L) || (defined(LIBRESSL_VERSION_NUMBER) && LIBRESSL_VERSION_NUMBER < 0x20700000L)
 static int
 RSA_set0_key(RSA *r, BIGNUM *n, BIGNUM *e, BIGNUM *d)
 {