CVS: Re-enable plugin unit tests

They had been lost while the latest refactorings.

Change-Id: I248b274c948a2265aa11d95bbeff143b4a439735
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/cvs/cvsplugin.h

@@ -90,6 +90,7 @@ public:
                      const QString &revision, int lineNumber);
 
 #ifdef WITH_TESTS
+private slots:
     void testDiffFileResolving_data();
     void testDiffFileResolving();
     void testLogResolving();