Similar to the FTS readdir fix in v4.6.0-72-g155c9d1, handle the last
two unhandled readdir(3) errors.
* find/pred.c (pred_empty): Do the above.
* lib/fdleak.c (get_proc_max_fd): Likewise. While at it, fix the
condition to only skip "." and ".."; previously, also other files
beginning with ".." would have been skipped - that was theoretically,
as we only expect the FD files in "/proc/self/fd".
7a6e548690