message: [storage] impl conversions from/to prost proto and GetTransactionsResponse
  Closes:
  Approved by: mimoo
diff: @@ -30,7 +30,7 @@ use failure::prelude::*;
  #[cfg(any(test, feature = "testing"))]
  use proptest_derive::Arbitrary;
  use proto_conv::{FromProto, IntoProto};
  -use std::convert::TryFrom;
  +use std::convert::{TryFrom, TryInto};
  use types::{
  account_address::AccountAddress,
  account_state_blob::AccountStateBlob,
  @@ -403,6 +403,27 @@ impl GetTransactionsResponse {
  }
  }
  +impl TryFrom<crate::proto::storage_prost::GetTransactionsResponse> for GetTransactionsResponse {
  + type Error = Error;
  +
  + fn try_from(proto: crate::proto::storage_prost::GetTransactionsResponse) -> Result<Self> {
  + Ok(GetTransactionsResponse {
  + txn_list_with_proof: proto
  + .txn_list_with_proof
  + .unwrap_or_else(Default::default)
  + .try_into()?,
  + })
  + }
  +}
  +
  +impl From<GetTransactionsResponse> for crate::proto::storage_prost::GetTransactionsResponse {
  + fn from(response: GetTransactionsResponse) -> Self {
  + Self {
  + txn_list_with_proof: Some(response.txn_list_with_proof.into()),
  + }
  + }
  +}
  +
  /// Helper to construct and parse [`proto::storage::StartupInfo`]
  ///
  /// It does so by implementing [`IntoProto`](#impl-IntoProto) and [`FromProto`](#impl-FromProto),
  