VcsBase: Replace a struct with class

Change-Id: I5895e759820a358cd1d54888bfe84ddccb484967
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/vcsbase/vcsbaseoutputwindow.cpp

@@ -264,8 +264,9 @@ void OutputWindowPlainTextEdit::setFormat(enum VcsBaseOutputWindow::MessageStyle
 } // namespace Internal
 
 // ------------------- VcsBaseOutputWindowPrivate
-struct VcsBaseOutputWindowPrivate
+class VcsBaseOutputWindowPrivate
 {
+public:
     static VcsBaseOutputWindow *instance;
     Internal::OutputWindowPlainTextEdit *plainTextEdit();
 

src/plugins/vcsbase/vcsbaseoutputwindow.h

@@ -36,7 +36,7 @@
 
 namespace VcsBase {
 
-struct VcsBaseOutputWindowPrivate;
+class VcsBaseOutputWindowPrivate;
 
 class VCSBASE_EXPORT VcsBaseOutputWindow : public Core::IOutputPane
 {