[4.0] 455281a Workaround a problem in recent libedit versions

[Federico G. Schwindt]

commit 455281a9eff278f831de26644fd08c21528667a1
Author: Federico G. Schwindt <fgsch at lodoss.net>
Date:   Mon Jun 30 13:08:42 2014 +0100

    Workaround a problem in recent libedit versions
    
    Reinstall the readline handler when we are called in order to clear the
    input line. Tested in a variety of versions by scn and myself.
    
    Fixes #1531

diff --git a/bin/varnishadm/varnishadm.c b/bin/varnishadm/varnishadm.c
index 60f36ba..0c2ecc1 100644
--- a/bin/varnishadm/varnishadm.c
+++ b/bin/varnishadm/varnishadm.c
@@ -184,6 +184,7 @@ static void send_line(char *l)
 		cli_write(_line_sock, l);
 		cli_write(_line_sock, "\n");
 		add_history(l);
+		rl_callback_handler_install("varnish> ", send_line);
 	} else {
 		RL_EXIT(0);
 	}