doveadm: Actually use resolved IP address(es) in director flush

It left the IP variable unitialized which caused host parameter
to be left empty causing flush all. Flushing with IP address
was not affected.

src/doveadm/doveadm-director.c

@@ -716,6 +716,7 @@ static void cmd_director_flush(struct doveadm_cmd_context *cctx)
 
 	cmd = t_str_new(64);
 	for (i = 0; i < ips_count; i++) {
+		ip = ips[i];
 		str_truncate(cmd, 0);
 		if (ctx->force_flush)
 			str_printfa(cmd, "HOST-FLUSH\t%s\n", net_ip2addr(&ip));