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

ethcore/light/src/net/load_timer.rs

@@ -32,7 +32,7 @@ use request::{CompleteRequest, Kind};
 
 use bincode;
 use time;
-use util::{RwLock, Mutex};
+use parking_lot::{RwLock, Mutex};
 
 /// Number of time periods samples should be kept for.
 pub const MOVING_SAMPLE_SIZE: usize = 256;