openvpn: update to 2.4.8

Backport two upstream commits that allow building
openvpn-openssl without OpenSSLs deprecated APIs.

Full changelog:
https://community.openvpn.net/openvpn/wiki/ChangesInOpenvpn24#OpenVPN2.4.8

Signed-off-by: Magnus Kroken <mkroken@gmail.com>

package/network/services/openvpn/patches/111-openssl-add-missing-include-statements.patch

@@ -0,0 +1,65 @@
+From 1987498271abadf042d8bb3feee1fe0d877a9d55 Mon Sep 17 00:00:00 2001
+From: Steffan Karger <steffan@karger.me>
+Date: Sun, 26 Nov 2017 16:49:12 +0100
+Subject: [PATCH] openssl: add missing #include statements
+
+Compiling our current master against OpenSSL 1.1 with
+-DOPENSSL_API_COMPAT=0x10100000L screams bloody murder.  This patch fixes
+the errors caused by missing includes.  Previous openssl versions would
+usually include 'the rest of the world', but they're fixing that.  So we
+should no longer rely on it.
+
+(And sneaking in alphabetic ordering of the includes while touching them.)
+
+Signed-off-by: Steffan Karger <steffan@karger.me>
+Acked-by: Gert Doering <gert@greenie.muc.de>
+Message-Id: <20171126154912.13283-1-steffan@karger.me>
+URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg15936.html
+Signed-off-by: Gert Doering <gert@greenie.muc.de>
+---
+ src/openvpn/openssl_compat.h     | 1 +
+ src/openvpn/ssl_openssl.c        | 6 +++++-
+ src/openvpn/ssl_verify_openssl.c | 3 ++-
+ 3 files changed, 8 insertions(+), 2 deletions(-)
+
+--- a/src/openvpn/openssl_compat.h
++++ b/src/openvpn/openssl_compat.h
+@@ -42,6 +42,7 @@
+ 
+ #include "buffer.h"
+ 
++#include <openssl/rsa.h>
+ #include <openssl/ssl.h>
+ #include <openssl/x509.h>
+ 
+--- a/src/openvpn/ssl_openssl.c
++++ b/src/openvpn/ssl_openssl.c
+@@ -52,10 +52,14 @@
+ 
+ #include "ssl_verify_openssl.h"
+ 
++#include <openssl/bn.h>
++#include <openssl/crypto.h>
++#include <openssl/dh.h>
++#include <openssl/dsa.h>
+ #include <openssl/err.h>
+ #include <openssl/pkcs12.h>
++#include <openssl/rsa.h>
+ #include <openssl/x509.h>
+-#include <openssl/crypto.h>
+ #ifndef OPENSSL_NO_EC
+ #include <openssl/ec.h>
+ #endif
+--- a/src/openvpn/ssl_verify_openssl.c
++++ b/src/openvpn/ssl_verify_openssl.c
+@@ -44,8 +44,9 @@
+ #include "ssl_verify_backend.h"
+ #include "openssl_compat.h"
+ 
+-#include <openssl/x509v3.h>
++#include <openssl/bn.h>
+ #include <openssl/err.h>
++#include <openssl/x509v3.h>
+ 
+ int
+ verify_callback(int preverify_ok, X509_STORE_CTX *ctx)