swapchain: Do not increase the age of 0-age slots
swapchain: Do not increase the age of 0-age slots

Slots with an age of 0 were never rendered to. This means
we should not increase their age, when others are submitted
or the renderer might wrongfully assume usuable contents are
available in the buffer.

Smithay/smithay,Smithay/smithay,Smithay/smithay,Smithay/smithay