block: Derive Debug on RawFileDisk

Add #[derive(Debug)] to RawFileDisk. This is required by the
new disk_file traits which have Send + Debug bounds.

Signed-off-by: Muminul Islam <muislam@microsoft.com>

block/src/raw_async.rs

@@ -18,6 +18,7 @@ use crate::{
     BatchRequest, DiskTopology, RequestType, SECTOR_SIZE, probe_sparse_support, query_device_size,
 };
 
+#[derive(Debug)]
 pub struct RawFileDisk {
     file: File,
 }