message: [Storage] Remove LibraDBWrapper
  Since we are no longer using grpcio, we probably don't the the previous
  issue (https://github.com/tikv/grpc-rs/issues/227) any more. So the
  wrapper can be removed.
  Closes:
  Approved by: zamsden
diff: @@ -21,7 +21,7 @@ use libra_types::proto::types::{
  UpdateToLatestLedgerRequest, UpdateToLatestLedgerResponse, ValidatorChangeProof,
  };
  use libradb::LibraDB;
  -use std::{convert::TryFrom, net::ToSocketAddrs, ops::Deref, path::Path, sync::Arc};
  +use std::{convert::TryFrom, net::ToSocketAddrs, path::Path, sync::Arc};
  use storage_proto::proto::storage::{
  storage_server::{Storage, StorageServer},
  BackupAccountStateRequest, BackupAccountStateResponse, GetAccountStateRangeProofRequest,
  @@ -59,35 +59,14 @@ pub fn start_storage_service(config: &NodeConfig) -> Runtime {
  /// [`LibraDB`].
  #[derive(Clone)]
  pub struct StorageService {
  - db: Arc<LibraDBWrapper>,
  -}
  -
  -struct LibraDBWrapper {
  - db: Option<LibraDB>,
  -}
  -
  -impl LibraDBWrapper {
  - pub fn new<P: AsRef<Path>>(path: &P) -> Self {
  - let db = LibraDB::new(path);
  - Self { db: Some(db) }
  - }
  -}
  -
  -impl Deref for LibraDBWrapper {
  - type Target = LibraDB;
  -
  - fn deref(&self) -> &Self::Target {
  - self.db.as_ref().expect("LibraDB is dropped unexpectedly")
  - }
  + db: Arc<LibraDB>,
  }
  impl StorageService {
  /// This opens a [`LibraDB`] at `path` and returns a [`StorageService`] instance serving it.
  pub fn new<P: AsRef<Path>>(path: &P) -> Self {
  - let db_wrapper = LibraDBWrapper::new(path);
  - Self {
  - db: Arc::new(db_wrapper),
  - }
  + let db = Arc::new(LibraDB::new(path));
  + Self { db }
  }
  }
  