[4.1] fb375e9 Do not add empty strings to the cli history

[Lasse Karstensen]

commit fb375e9bdd25c60c5900e0b262ff452fd95e4317
Author: Federico G. Schwindt <fgsch at lodoss.net>
Date:   Tue Apr 19 13:16:23 2016 +0100

    Do not add empty strings to the cli history

diff --git a/bin/varnishadm/varnishadm.c b/bin/varnishadm/varnishadm.c
index 621d696..e426f0b 100644
--- a/bin/varnishadm/varnishadm.c
+++ b/bin/varnishadm/varnishadm.c
@@ -190,7 +190,8 @@ static void send_line(char *l)
 	if (l) {
 		cli_write(_line_sock, l);
 		cli_write(_line_sock, "\n");
-		add_history(l);
+		if (*l)
+			add_history(l);
 		rl_callback_handler_install("varnish> ", send_line);
 	} else {
 		RL_EXIT(0);