nut: added compatibility with openssl-1.1

Also added a fix in a check for empty string.

Signed-off-by: Eneas U de Queiroz <cote2004-github@yahoo.com>

net/nut/patches/0002-Fix-check-for-empty-string.patch

@@ -0,0 +1,25 @@
+From 2ef929da38232af63ba53074ca97e95ae4faf912 Mon Sep 17 00:00:00 2001
+From: Arjen de Korte <build+lede@de-korte.org>
+Date: Tue, 28 Nov 2017 22:01:41 +0100
+Subject: [PATCH 2/2] Fix check for empty string
+
+---
+ clients/upssched.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/clients/upssched.c b/clients/upssched.c
+index 97b3ed42..3fdf118e 100644
+--- a/clients/upssched.c
++++ b/clients/upssched.c
+@@ -794,7 +794,7 @@ static void parse_at(const char *ntype, const char *un, const char *cmd,
+ 	}
+ 
+ 	if (!strcmp(cmd, "EXECUTE")) {
+-		if (ca1 == '\0') {
++		if (ca1[0] == '\0') {
+ 			upslogx(LOG_ERR, "Empty EXECUTE command argument");
+ 			return;
+ 		}
+-- 
+2.16.1
+