Clean exported headers of the VcsBase plugin.

Change-Id: Ibfe20bc7156e14e33fd0448586f5cc625494e008
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/vcsbase/vcsbaseclient.h

@@ -32,7 +32,6 @@
 #define VCSBASECLIENT_H
 
 #include "vcsbase_global.h"
-#include <coreplugin/id.h>
 
 #include <QObject>
 #include <QStringList>
@@ -45,6 +44,8 @@ class QVariant;
 class QProcessEnvironment;
 QT_END_NAMESPACE
 
+namespace Core { class Id; }
+
 namespace Utils {
 struct SynchronousProcessResponse;
 class ExitCodeInterpreter;