argv was set but unused

Also gives an error message when you gave it a parameter it didn't expect.

Reviewed-by: Rich Salz <rsalz@openssl.org>

MR: #2009

apps/s_client.c

@@ -1341,7 +1341,8 @@ int s_client_main(int argc, char **argv)
         }
     }
     argc = opt_num_rest();
-    argv = opt_rest();
+    if (argc != 0)
+        goto opthelp;
 
     if (proxystr) {
         int res;