more make check fixes

Signed-off-by: limbooverlambda <schakra1@gmail.com>

src/kv/key.rs

@@ -2,7 +2,6 @@
 
 use std::fmt;
 use std::ops::Bound;
-use std::u8;
 
 #[allow(unused_imports)]
 #[cfg(test)]

src/kv/mod.rs

@@ -1,6 +1,5 @@
 // Copyright 2019 TiKV Project Authors. Licensed under Apache-2.0.
 use std::fmt;
-use std::u8;
 
 mod bound_range;
 pub mod codec;

src/raw/client.rs

@@ -3,7 +3,6 @@
 use core::ops::Range;
 use std::str::FromStr;
 use std::sync::Arc;
-use std::u32;
 
 use futures::StreamExt;
 use log::debug;

src/transaction/requests.rs

@@ -252,7 +252,7 @@ pub fn new_prewrite_request(
     req.start_version = start_version;
     req.lock_ttl = lock_ttl;
     // FIXME: Lite resolve lock is currently disabled
-    req.txn_size = std::u64::MAX;
+    req.txn_size = u64::MAX;
 
     req
 }