Fix issue #2230: First click on order dialog is ignored 

Try to fix [issue #2230](https://code.google.com/p/tortoisegit/issues/detail?id=2230)

CLogOrdering::DoModal() might not be called in CLogDlg::OnLvnColumnclick().
I am not sure what the reason is. I guess lacking the mouse L button up event.

P.S.
The first commit is not related to the issue 2230. :)