leave the read loop on an unknown packet. we might have overread some…

…how. (reported by email, user had shortened the file on the SD card, camera still offered original size)

camlibs/ptp2/ptpip.c

@@ -370,6 +370,7 @@ ptp_ptpip_getdata (PTPParams* params, PTPContainer* ptp, PTPDataHandler *handler
 			continue;
 		}
 		GP_LOG_E ("ret type %d", hdr.type);
+		break;
 	}
 	if (curread < toread)
 		return PTP_RC_GeneralError;