Don't skip the last entry in the logbook buffer

Due to an off by one error, the last entry in the logbook buffer wasn't
processed at all. In theory that means the oldest dive is skipped and
can't be downloaded. However the logbook buffer usually contains some
empty entries at the front. Those are already detected by inspecting the
dive number for a zero value and thus the download is already aborted
before reaching that last entry. Therefore this bug didn't cause any
problems yet in practice.

Author: jefdriesen

src/cressi_goa.c

@@ -431,7 +431,7 @@ cressi_goa_device_foreach (dc_device_t *abstract, dc_dive_callback_t callback, v
 	// Count the number of dives.
 	unsigned int count = 0;
 	unsigned int offset = logbook_size;
-	while (offset > SZ_HEADER) {
+	while (offset >= SZ_HEADER) {
 		// Move to the start of the logbook entry.
 		offset -= SZ_HEADER;