path.c: mark 'logs/HEAD' in 'common_list' as file

'logs/HEAD', i.e. HEAD's reflog, is a file, but its entry in 'common_list' has the 'is_dir' bit set. Unset that bit to make it consistent with what 'logs/HEAD' is supposed to be. This doesn't make a difference in behavior: check_common() is the only function that looks at the 'is_dir' bit, and that function either returns 0, or '!exclude', which for 'logs/HEAD' results in 0 as well. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>