Cvs: Fix crash on load

Amends 1cd936c531

Change-Id: I14239730bc079be570f060ce48cb84eb2bfe02d4
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

src/plugins/cvs/cvsplugin.cpp

@@ -212,6 +212,7 @@ void CvsPlugin::extensionsInitialized()
 CvsPluginPrivate::CvsPluginPrivate()
 {
     using namespace Core::Constants;
+    dd = this;
 
     Context context(CVS_CONTEXT);