Fix vkGetDeviceQueue2 segfault when returned vkQueue is VK_NULL_HANDLE
Fix vkGetDeviceQueue2 segfault when returned vkQueue is VK_NULL_HANDLE

This affects the Loader.

Change-Id: I05a3feb87781be773f30327601a2bf86a53ae115

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools