FakeVim: clear command buffer when leving fakevim.

Some recent regression left an "--  --" in there.

Change-Id: Ibd587011e2dc80f3fe3e46cdc78c55d934a50b66
Reviewed-by: Lukas Holecek <hluk@email.cz>
Reviewed-by: hjk <qthjk@ovi.com>

src/plugins/fakevim/fakevimplugin.cpp

@@ -161,6 +161,7 @@ public:
 
         if (m_eventFilter != eventFilter) {
             if (m_eventFilter != 0) {
+                m_label->setText(QString());
                 m_edit->removeEventFilter(m_eventFilter);
                 disconnect(SIGNAL(edited(QString,int)));
             }