Only offer to show dive on map if we have location information

[Dirk Hohndel]

Linus Torvalds <torvalds at linux-foundation.org> writes:

> This adds the "Show in map" menu entry to the divelist only if we
> actually have a location to show.
>
> Of course, having some way to visually see whether we have a GPS
> location even before we show the menu would probably be good. Maybe a
> marker in the "location" string or something. But in the meanwhile, at
> least we don't have that menu entry if we have nothing to show.

I will accept this patch. I was thinking of maybe having a little GPS
icon before the location text for those that have a GPS location. And
for extra credit, clicking on that icon opens the map view?

/D