Core: pass dive, cylinder-id to fill_default_cylinder

The fill_default_cylinder() function calculated the MOD based
on the currently displayed dive. This does not seem to make sense:
- When importing dives, why would we care about the altitude and
  salinity of the currently displayed dive, possibly from a different
  trip.
- The planner is supposed to be thread-safe and should not touch
  global variables.

Of course this means that the importing-functions have to fill
out altitude and salinity before creating the default cylinder,
but this is their problem. For a freshly created dive they will
get the default values, which still seems less random than the
values from the displayed dive.

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

core/libdivecomputer.c

@@ -224,7 +224,7 @@ static int parse_gasmixes(device_data_t *devdata, struct dive *dive, dc_parser_t
 		if (no_volume) {
 			/* for the first tank, if there is no tanksize available from the
 			 * dive computer, fill in the default tank information (if set) */
-			fill_default_cylinder(&dive->cylinder[i]);
+			fill_default_cylinder(dive, i);
 		}
 		/* whatever happens, make sure there is a name for the cylinder */
 		if (empty_string(dive->cylinder[i].type.description))