Remove unused sysdeps/unix/{,sysv/}getdents.c

[Roland McGrath]

> 2012-04-24  Joseph Myers  <joseph@codesourcery.com>
> 
> 	* sysdeps/unix/getdents.c: Remove file.
> 	* sysdeps/unix/sysv/getdents.c: Likewise.
> 	* sysdeps/unix/sysv/syscalls.list (s_getdents): Remove.

OK.