VcsBase: Turn State into a class

Change-Id: I1e0a9e6f4468ad29b70dc1fd78310ccb6a2133f3
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/vcsbase/vcsbaseplugin.cpp

@@ -91,8 +91,9 @@ namespace Internal {
     Aggregated in the QSharedData of VcsBase::VcsBasePluginState.
 */
 
-struct State
+class State
 {
+public:
     void clearFile();
     void clearPatchFile();
     void clearProject();

src/plugins/vcsbase/vcsbaseplugin.h

@@ -59,7 +59,7 @@ class IDocument;
 
 namespace VcsBase {
 
-namespace Internal { struct State; }
+namespace Internal { class State; }
 
 class VcsBaseSubmitEditor;
 class VcsBasePluginPrivate;