remove re-export of parking_lot in util (#6435)

stratum/Cargo.toml

@@ -23,5 +23,6 @@ semver = "0.6"
 ethcore-ipc-nano = { path = "../ipc/nano" }
 futures = "0.1"
 tokio-core = "0.1"
+parking_lot = "0.4"
 ethcore-logger = { path = "../logger" }
 hash = { path = "../util/hash" }

stratum/src/lib.rs

@@ -26,6 +26,7 @@ extern crate semver;
 extern crate futures;
 extern crate ethcore_logger;
 extern crate hash;
+extern crate parking_lot;
 
 #[cfg(test)] extern crate tokio_core;
 extern crate ethcore_devtools as devtools;
@@ -56,7 +57,8 @@ use std::sync::Arc;
 use std::net::SocketAddr;
 use std::collections::{HashSet, HashMap};
 use hash::keccak;
-use util::{H256, RwLock, RwLockReadGuard};
+use parking_lot::{RwLock, RwLockReadGuard};
+use util::H256;
 
 type RpcResult = BoxFuture<jsonrpc_core::Value, jsonrpc_core::Error>;