rm: fix a tiny, nearly inconsequential bug.

rm: fix a tiny, nearly inconsequential bug.

Don't perform a "."-relative lstat, when the file in question
may well not be in ".".  Although this is a bug, a few attempts
to exercise it on a linux-2.6.22 system failed.  You probably need
a pre-openat system to trigger the failure.  The consequence of this
bug would be a lower-quality diagnostic upon failed dir removal.
* src/remove.c (is_dir_lstat): Add a parameter, fd_cwd.
Use it instead of hard-coding AT_FDCWD.
(remove_entry): Call is_dir_lstat with fd_cwd.

Signed-off-by: Jim Meyering <jim@meyering.net>