BUG/MINOR: log: Initialize the list element when allocating a new log server

211ea252d ("BUG/MINOR: logs: fix logsrv leaks on clean exit") introduced a
regression because the list element of a new log server is not intialized. Thus
HAProxy crashes on error path when an invalid log server is released.

This patch shoud fix the issue #1636. It must be backported if the above commit
is backported. For now, it is 2.6-specific and no backport is needed.

src/log.c

@@ -842,7 +842,7 @@ int parse_logsrv(char **args, struct list *logsrvs, int do_del, const char *file
 		memprintf(err, "out of memory");
 		goto error;
 	}
-
+	LIST_INIT(&logsrv->list);
 	logsrv->conf.file = strdup(file);
 	logsrv->conf.line = linenum;