message: Log the specific error if vkCreateInstance fails in demo program
diff: @@ -265,7 +265,11 @@ void VulkanGraphicsTest::Prepare(int argc, char **argv)
  vkh::InstanceCreateInfo(app, enabledLayers, enabledInstExts).next(instInfoNext), NULL,
  &inst);
  - if(vkr == VK_SUCCESS)
  + if(vkr != VK_SUCCESS)
  + {
  + TEST_ERROR("Error initialising vulkan instance: %d", vkr);
  + }
  + else
  {
  volkLoadInstance((VkInstance)inst);
  