check-ignore: fix mix of directories and other file types

check-ignore: fix mix of directories and other file types

In check_ignore(), the first pathspec item determines the dtype for any
subsequent ones.  That means that a pathspec matching a regular file can
prevent following pathspecs from matching directories, which makes no
sense.  Fix that by determining the dtype for each pathspec separately,
by passing the value DT_UNKNOWN to last_exclude_matching() each time.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>