VcsManager: Add convenience signal for Vcs config changes

Change-Id: Iac7b80fca94eee428650f0a53af8c2c1c46e6f89
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/coreplugin/vcsmanager.h

@@ -98,6 +98,7 @@ public:
 
 signals:
     void repositoryChanged(const QString &repository);
+    void configurationChanged(const IVersionControl *vcs);
 
 public slots:
     static void clearVersionControlCache();