* Output of `node_modules/.bin/electron --version`: 2.0.12
* Operating System (Platform and Version): Windows 10

**Expected Behavior**
`moveItemToTrash` should return `false` if the file is locked.

**Actual behavior**
`moveItemToTrash` does not return `false` when a file is locked.

**To Reproduce**
* open a folder in a command prompt (cd into it)
* run `shell.moveItemToTrash(path of folder)`
* observe the returned value is `true` indicating this operation was successful
shell/common/platform_util_win.cc
InterlockedIncrement(&m_cRef);
  return m_cRef;
}
ULONG DeleteFileProgressSink::Release() {
  
  ULONG ulRefCount = InterlockedDecrement(&m_cRef);
  if (0 == m_cRef) {
    delete this;
  }
  return ulRefCount;
}
HRESULT DeleteFileProgressSink::StartOperations() {
  return S_OK;
}
HRESULT DeleteFileProgressSink::FinishOperations(HRESULT) {
  return S_OK;
}
HRESULT DeleteFileProgressSink::PreRenameItem(DWORD, IShellItem*, LPCWSTR) {