Ensure Device::active_queue_families contain no duplicates

[NiklasJonsson]

• Added an entry to CHANGELOG_VULKANO.md or CHANGELOG_VK_SYS.md if knowledge of this change could be valuable to users
• Updated documentation to reflect any user-facing changes - in this repository
• Updated documentation to reflect any user-facing changes - PR to the guide that fixes existing documentation invalidated by this PR.

Each entry in Device::active_queue_families should be unique (as I've understood it). See for example the creation of ImmutableBuffer in Immutable::raw_impl, which will set the sharing mode to Concurrent if we have more than one (used) queue family on the device.

[knappador]

Seems like a bug =)

which will set the sharing mode to Concurrent if we have more than one (used) queue family on the device.

This choice seems like a hack to delay implementing the buffer ownership?

There's a lot of ugly stuff in this file.

The change is more correct than what was there, so I would be happy to merge it if someday I get organization membership @rukai @tomaka

[NiklasJonsson]

So is anything gonna happen here? Is there something else I should do?

[rukai]

Hey sorry about the wait, I am now putting my time into wgpu instead.

Good catch.
This change fixes an invalid usage of VkBufferCreateInfo and VKImageCreateInfo

If sharingMode is VK_SHARING_MODE_CONCURRENT, each element of pQueueFamilyIndices must be unique and must be less than pQueueFamilyPropertyCount returned by either vkGetPhysicalDeviceQueueFamilyProperties or vkGetPhysicalDeviceQueueFamilyProperties2 for the physicalDevice that was used to create device