file_exists() calls dos_to_unix()

[Luke Kenneth Casson Leighton]

> What, that you didn't add the lines of code (I assure you
> that you did :-) or that you don't recall it :-) ?

he he.  no i didn't: the file i specifically documented, in the comments
above, is two lists of rids.  i don't think i would have then gone and
called pwdb_gid_to_xxxx_rid() on them, particularly in that way.  i would
have created a function that read them in and individually made a rid out
of the gid.

not my style, in other words.