If a filename doesn't have a trailing slash, and we use QMimeDatabase::matchTypeForFile(MatchExtension) to guess its mimetype,
it results in application/octet-stream (generic type returned if QMimeDatabase wasn't able to guess) instead of inode/directory.
Because of that, indexer does try to index folders (not a big problem, but still...)
Since we've already use QFileInfo, use isDir check instead.