Git - Bug fix in changeSelectionDialog

disable checkout button too

Change-Id: I325436672091c6f4f824ed263c2643ecf31f93f4
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/git/changeselectiondialog.cpp

@@ -157,6 +157,7 @@ void ChangeSelectionDialog::enableButtons(bool b)
     m_showButton->setEnabled(b);
     m_cherryPickButton->setEnabled(b);
     m_revertButton->setEnabled(b);
+    m_checkoutButton->setEnabled(b);
 }
 
 void ChangeSelectionDialog::recalculateDetails(const QString &ref)