Remove pop + push logic

Author: a1phyr

wgpu-hal/src/vulkan/descriptor.rs

@@ -335,14 +335,14 @@ impl DescriptorBucket {
     }
 
     unsafe fn cleanup(&mut self, device: &super::DeviceShared) {
-        while let Some(pool) = self.pools.pop_front() {
-            if pool.allocated != 0 {
-                self.pools.push_front(pool);
+        while self.pools.len() > 1 {
+            if self.pools.front().unwrap().allocated != 0 {
                 break;
             }
 
             log::trace!("Destroying old descriptor pool");
 
+            let pool = self.pools.pop_front().unwrap();
             unsafe { device.raw.destroy_descriptor_pool(pool.raw, None) };
             self.offset += 1;
         }