bug#15735: 24.3.50; `find-library' completion bug

[Drew Adams <drew.adams@oracle.com>]

> > Debugger entered--Lisp error: (error "Can't find library ess-
> > 5.3.10/")
> 
> From this error message, it looks like it did not complete to
> "ess-5.3.10" but to "ess-5.3.10/", from which I gather that this is
> the directory you added (you added it inside a directory which is
> itself in load-path).

That's right.  It is a subdirectory of a directory in `load-path'.
It is not, itself, in `load-path'.

> So that looks perfectly correct.  Or am I misunderstanding
> something?

It doesn't seem right to me, but I'm probably naive.  I wouldn't
think that it should be a completion at all, since (a) it is not
itself an Emacs-Lisp library in the load-path and (b) there are
no such libraries within it.  I would expect TAB to say that there
are no completions.

I would expect that even if this directory were itself a member
of the load-path (which it is not).

But if this is the intended design, no problem.  It just didn't
seem like TRT to me.  IOW, I didn't expect it.