Fix windows build warnings

vm/src/stdlib/winreg.rs

@@ -2,9 +2,8 @@
 
 use crate::common::lock::{PyRwLock, PyRwLockReadGuard, PyRwLockWriteGuard};
 use crate::{
-    builtins::{PyStrRef, PyTypeRef},
-    exceptions::IntoPyException,
-    PyClassImpl, PyObjectRef, PyRef, PyResult, PyValue, TryFromObject, VirtualMachine,
+    builtins::PyStrRef, exceptions::IntoPyException, PyClassImpl, PyObjectRef, PyRef, PyResult,
+    PyValue, TryFromObject, VirtualMachine,
 };
 use std::convert::TryInto;
 use std::ffi::OsStr;