* 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
HRESULT STDMETHODCALLTYPE PreCopyItem(DWORD,
                                        IShellItem*,
                                        IShellItem*,
                                        LPCWSTR) override;
  HRESULT STDMETHODCALLTYPE PostCopyItem(DWORD,
                                         IShellItem*,
                                         IShellItem*,
                                         LPCWSTR,
                                         HRESULT,
                                         IShellItem*) override;
  HRESULT STDMETHODCALLTYPE PreDeleteItem(DWORD, IShellItem*) override;
  HRESULT STDMETHODCALLTYPE PostDeleteItem(DWORD,
                                           IShellItem*,
                                           HRESULT,
                                           IShellItem*) override;
  HRESULT STDMETHODCALLTYPE PreNewItem(DWORD, IShellItem*, LPCWSTR) override;
  HRESULT STDMETHODCALLTYPE PostNewItem(DWORD,
                                        IShellItem*,
                                        LPCWSTR,
                                        LPCWSTR,
                                        DWORD,
                                        HRESULT,
                                        IShellItem*) override;
  HRESULT STDMETHODCALLTYPE UpdateProgress(UINT, UINT) override;
  HRESULT STDMETHODCALLTYPE ResetTimer(void) override;
  HRESULT STDMETHODCALLTYPE PauseTimer(void) override;
  HRESULT STDMETHODCALLTYPE ResumeTimer(void) override;
  ULONG m_cRef;
};
DeleteFileProgressSink::DeleteFileProgressSink() {