make sure we don't download pieces while the torrent is checking

src/peer_connection.cpp

@@ -3292,6 +3292,13 @@ namespace libtorrent
 			return;
 		}
 
+		// we can't download pieces in these states
+		if (t->state() == torrent_status::checking_files
+			|| t->state() == torrent_status::checking_resume_data
+			|| t->state() == torrent_status::downloading_metadata
+			|| t->state() == torrent_status::allocating)
+			return;
+
 		if ((int)m_download_queue.size() >= m_desired_queue_size
 			|| t->upload_mode()) return;