Spelling fix in comment

Rebased-By: Wladimir J. van der Laan <laanwj@gmail.com>
Rebased-From: 3704a6a

src/qt/bitcoingui.cpp

@@ -188,7 +188,7 @@ BitcoinGUI::BitcoinGUI(bool fIsTestnet, QWidget *parent) :
 
     connect(openRPCConsoleAction, SIGNAL(triggered()), rpcConsole, SLOT(show()));
 
-    // prevents an oben debug window from becoming stuck/unusable on client shutdown
+    // prevents an open debug window from becoming stuck/unusable on client shutdown
     connect(quitAction, SIGNAL(triggered()), rpcConsole, SLOT(hide()));
 
     // Install event filter to be able to catch status tip events (QEvent::StatusTip)