chdir-safer can go?

[Paul Eggert]

As a result of the recent changes, the files lib/chdir-safer.c,
lib/chdir-safer.h, and m4/chdir-safer.m4 can be removed from
coreutils.  This is because mkdir-p no longer uses the open/fchdir
method; it simply uses mkdir, on the theory that you can't close the
race condition between mkdir and the next operation anyway, and the
file names are typically so short that there's no real performance
benefit to the O(N) algorithm.

Any objections to removing the chdir-safer files?  I guess we can
bring them back later if we find a use for them.  (On the other hand,
maybe you want me to try to bring back the O(N) algorithm....)