State db random fixes (#802)

* state-db: typo fixes

* use fmt::Result for 'fmt'

* state-db: typo fixes

* state-db: use the same pattern to pass the parameter

* state-db: follow the same style

substrate/core/client/db/src/lib.rs

@@ -420,7 +420,7 @@ impl<Block: BlockT> Backend<Block> {
 
 		Ok(Backend {
 			storage: Arc::new(storage_db),
-			tries_change_storage: tries_change_storage,
+			tries_change_storage,
 			blockchain,
 			canonicalization_delay,
 		})