Dive site: replace UUID_ROLE by DIVESITE_ROLE

Access to dive-sites in the LocationInformationModel was via UUID.
Replace this by a direct access to the struct dive_site pointer.
Accordingly, rename the UUID_ROLE to DIVESITE_ROLE.

This is a small step in replacing dive-site UUIDs by pointers
throughout the code base.

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

qt-models/divelocationmodel.cpp

@@ -59,8 +59,8 @@ QVariant LocationInformationModel::getDiveSiteData(const struct dive_site *ds, i
 		else
 			return QVariant();
 	}
-	case UUID_ROLE:
-		return ds->uuid;
+	case DIVESITE_ROLE:
+		return QVariant::fromValue<void *>((void *)ds); // Not nice: casting away const
 	}
 	return QVariant();
 }