librc: Don't include stacked runlevels in ls_dir with LS_INITD.

ls_dir is used to list services in a runlevel, in which directories are
stacked runlevels, not init scripts. And in general, folders are not
allowed in init.d dirs anyway.

src/librc/librc.c

@@ -94,7 +94,8 @@ ls_dir(const char *dir, int options)
  xasprintf(&file, "%s/%s", dir, d->d_name);
  r = stat(file, &buf);
  free(file);
- if (r != 0)
+ /* stacked runlevels are not init scripts */
+ if (r != 0 || S_ISDIR(buf.st_mode))
  continue;
 
  /* .sh files are not init scripts */