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/basevcssubmiteditorfactory.cpp

@@ -37,10 +37,6 @@ VcsSubmitEditorFactory::VcsSubmitEditorFactory
     addMimeType(parameters->mimeType);
 }
 
-VcsSubmitEditorFactory::~VcsSubmitEditorFactory()
-{
-}
-
 Core::IEditor *VcsSubmitEditorFactory::createEditor()
 {
     return m_editorCreator();