Text description of GOST signature algorithms

Reviewed-by: NBernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6168)

apps/s_cb.c

@@ -234,6 +234,15 @@ static const char *get_sigtype(int nid)
      case NID_ED448:
         return "Ed448";
 
+     case NID_id_GostR3410_2001:
+        return "gost2001";
+
+     case NID_id_GostR3410_2012_256:
+        return "gost2012_256";
+
+     case NID_id_GostR3410_2012_512:
+        return "gost2012_512";
+
     default:
         return NULL;
     }