vim: Use correct name for single vimscript files.

Just threw me out of zone, because I was terribly annoyed on why the
hell Python indentation isn't done correctly anymore. If the file path
is something like "indent/script4316.vim", Vim won't load it because
it's searching for "indent/$ftname.vim".

Signed-off-by: aszlig <aszlig@redmoonstudios.org>