CMakeOpenProjectWizard: Explicitly add a "cancel" button.

Task-number: QTCREATORBUG-9264
Change-Id: I7c726177ff855da41d1971245655e8dc24740430
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/cmakeprojectmanager/cmakeopenprojectwizard.cpp

@@ -266,6 +266,7 @@ CMakeOpenProjectWizard::CMakeOpenProjectWizard(CMakeManager *cmakeManager, CMake
 void CMakeOpenProjectWizard::init()
 {
     setOption(QWizard::NoBackButtonOnStartPage);
+    setOption(QWizard::NoCancelButton, false);
     setWindowTitle(tr("CMake Wizard"));
 }