Patch to allow trailing dots on managed mounts

[Pierre A. Humblet]

cgf wrote:

> Is it correct to assume that only fhandler_base::open cares about
>trailing dots?

Good point. This bring back memories.

The initial motivation was to fix problems introduced by the 
use of NtCreateFile 

http://www.cygwin.com/ml/cygwin/2004-04/msg01250.html
and there were successive changes

2004-04-30  Corinna Vinschen  <corinna@vinschen.de>

        * path.cc (normalize_posix_path): Remove trailing dots and spaces.

http://cygwin.com/ml/cygwin-patches/2004-q2/msg00053.html

2004-05-06  Pierre Humblet <pierre.humblet@ieee.org>

        * path.cc (path_conv::check): Strip trailing dots and spaces and
        return error if the final component had only dots and spaces.
        (normalize_posix_path): Revert 2004-04-30.

However, as a side effect, checking the tail in :check
also cleanly fixed longstanding dormant issues with the path hash
and with chroot (at least).

So checking the tail in fhandler_base::open() is too late.
It should be done before exiting  :check(), perhaps only in the
case where the path refers to a disk file, preferably
with little processing overhead.

Although it wasn't done before 2004/04, we should also make sure
(I have no free time for the moment) that nothing goes wrong 
inside :check() while we lookup symbolic links.

Pierre