bug#16406: load prefers directories rather than searching load-path

[Eli Zaretskii]

> From: npostavs@users.sourceforge.net
> Date: Sat, 03 Sep 2016 12:43:29 -0400
> Cc: 16406@debbugs.gnu.org
> 
> > Seems simple enough to fix, here is a patch (this also covers #17848
> > "add suffix search to -l even when directory part in argument"):
> 
> That one broke normal loading.  Here's a new patch.

Instead of doing the search by hand, wouldn't it be better to teach
'load' to ignore directories?  Or do we have a use case where finding
a directory in 'load' would make sense?

IOW, isn't "'load' prefers directories" the actual problem we should
fix, rather than only fixing the startup problem?

I do agree that the file-exists-p test in command-line-1 should be
replaced with a test that doesn't let directories through.  But I
don't understand why using locate-file here is a good idea.

Thanks.