Fix lightning gun handling for corpses and single player podiums

The lightning trail is fired from the real non-predicted entity for
the local client so it can show the server location. The real client
entity was always used to check if a player entity is firing the
lighting gun. This potentially causes corpses and players on single
player podiums with lightning gun to render the lightning trail if
the real (living) client is firing the lightning gun.

I'm not aware of this causing any issues without modifying the game
logic. Corpses have no weapon and it's not possible to fire during
single player intermission.

code/cgame/cg_weapons.c

@@ -1286,7 +1286,7 @@ void CG_AddPlayerWeapon( refEntity_t *parent, playerState_t *ps, centity_t *cent
 	}
 
 	// make sure we aren't looking at cg.predictedPlayerEntity for LG
-	nonPredictedCent = &cg_entities[cent->currentState.clientNum];
+	nonPredictedCent = &cg_entities[cent->currentState.number];
 
 	// if the index of the nonPredictedCent is not the same as the clientNum
 	// then this is a fake player (like on the single player podiums), so