MFC rmdir.2 1.14 and 1.15, and undelete.2 1.16 and 1.17

rmdir() fails with EINVAL if the last component of the path is "..".
Document the previously undocumented behaviour of rmdir(".") returning
EINVAL as required by POSIX and SUSv3. Bump the man page change date.

undelete() fails with EINVAL if the last component of the path is "..".
Bump the man page change date.