Fix crash when creeper explodes in minecart

mods/ENTITIES/mcl_burning/api.lua

@@ -5,7 +5,12 @@ function mcl_burning.get_storage(obj)
 end
 
 function mcl_burning.is_burning(obj)
-	return mcl_burning.get_storage(obj).burn_time
+	local storage = mcl_burning.get_storage(obj)
+	if storage then
+		return mcl_burning.get_storage(obj).burn_time
+	else
+		return false
+	end
 end
 
 function mcl_burning.is_affected_by_rain(obj)

mods/ENTITIES/mcl_minecarts/init.lua

@@ -370,13 +370,10 @@ local function register_entity(entity_id, mesh, textures, drop, on_rightclick, o
 					end
 				end
 			end
-		-- Make room in the minecart after the mob dies
 		elseif self._passenger then
-			if math.random(1,20) == 1 then
-				local dead = self._passenger:check_for_death()
-				if dead == true then
-					self._passenger = nil
-				end
+			local passenger_pos = self._passenger.object:get_pos()
+			if not passenger_pos then
+				self._passenger = nil
 			end
 		end