2 tiny modification on snapshot (#8601)

* Some tiny modifications.
1. fix some typo in the comment.
2. sort the order of methods in 'impl state::Backend for StateDB`

* Remove the clone of code_cache, as it has been done in clone_basic.

* remove From::from. It seems not necessary.

* change mode: remove rust files' executable mode.

* 2 tiny modifications on snapshot.

ethcore/src/snapshot/consensus/work.rs

@@ -229,7 +229,7 @@ impl Rebuilder for PowRebuilder {
 		let item_count = rlp.item_count()?;
 		let num_blocks = (item_count - 3) as u64;
 
-		trace!(target: "snapshot", "restoring block chunk with {} blocks.", item_count - 3);
+		trace!(target: "snapshot", "restoring block chunk with {} blocks.", num_blocks);
 
 		if self.fed_blocks + num_blocks > self.snapshot_blocks {
 			return Err(Error::TooManyBlocks(self.snapshot_blocks, self.fed_blocks + num_blocks).into())

ethcore/src/snapshot/service.rs

@@ -176,7 +176,7 @@ impl Restoration {
 		// verify final state root.
 		let root = self.state.state_root();
 		if root != self.final_state_root {
-			warn!("Final restored state has wrong state root: expected {:?}, got {:?}", root, self.final_state_root);
+			warn!("Final restored state has wrong state root: expected {:?}, got {:?}", self.final_state_root, root);
 			return Err(TrieError::InvalidStateRoot(root).into());
 		}