VcsBase: Modernize headers

* Use pragma once
* Use override
* Remove Q_DECLARE_PRIVATE as that makes no sense for QtCreator

Change-Id: Ic31d4868c172a0b8fcb50cc9a71a6e95639cf84c
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/vcsbase/commonvcssettings.h

@@ -23,8 +23,7 @@
 **
 ****************************************************************************/
 
-#ifndef COMMONVCSSETTINGS_H
-#define COMMONVCSSETTINGS_H
+#pragma once
 
 #include <QString>
 
@@ -66,5 +65,3 @@ QDebug operator<<(QDebug, const CommonVcsSettings &);
 
 } // namespace Internal
 } // namespace VcsBase
-
-#endif // COMMONVCSSETTINGS_H