if $directory_transport is a file, it could be a filterfile. So far, so
good.
if the "/" is missing at the end of a directory path, it's considered to
be a filter file,
and thats wrong.
@Devs:
Pls add a check for the $directory_transport variable, if the string is
indeed a file or a directory and
act accordingly as a directory can never be a mbox file, or a
filterfile, it will always be a mdir directory.