Cleanup: free dive table in trips and dive sites

Trips and dive sites were changed to use dive tables instead
of linked lists. But the memory used for the tables wasn't freed.
Do this.

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

core/divelist.c

@@ -715,6 +715,7 @@ void free_trip(dive_trip_t *trip)
 	if (trip) {
 		free(trip->location);
 		free(trip->notes);
+		free(trip->dives.dives);
 		free(trip);
 	}
 }

core/divesite.c

@@ -207,6 +207,7 @@ void free_dive_site(struct dive_site *ds)
 		free(ds->name);
 		free(ds->notes);
 		free(ds->description);
+		free(ds->dives.dives);
 		free_taxonomy(&ds->taxonomy);
 		free(ds);
 	}