Fix clear value array in textoverlay
Fix clear value array in textoverlay

According to section 7.4. Render Pass Commands of the Vulkan spec,
VkRenderPassBeginInfo::pClearValues is indexed by attachment number.
Since the second attachment in the renderpass will be cleared, a clear
value array of length two is required, and the second element of that
array must be assigned the desired clear value.

SaschaWillems/Vulkan,jpbruyere/Vulkan,martty/Vulkan,SaschaWillems/Vulkan,jherico/Vulkan,jpbruyere/Vulkan,SaschaWillems/Vulkan,jherico/Vulkan,dreadwords/Vulkan,ming4883/Vulkan,SaschaWillems/Vulkan,grim210/Vulkan,SaschaWillems/Vulkan,grim210/Vulkan,ming4883/Vulkan,ming4883/Vulkan