Cleanup: remove DownloadFromDCThread::tripTable

Since ff9506b21bbb9910256841dcb577bcb2e19047e8 the downloaders don't
add dives to a new trip and therefore the tripTable field of
DownloadFromDCThread became pointless. Remove it.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

core/downloadfromdcthread.h

@@ -70,7 +70,6 @@ public:
 
 private:
 	struct dive_table downloadTable;
-	struct trip_table tripTable;
 	DCDeviceData *m_data;
 };