QCborContainerPrivate: honor the RO5

The class defines a destructor, but it's also meant to be copy/move
constructible (being a shared data for QCbor* classes). On the same
note, the class is not meant to be assignable, as doing so would corrupt
the refcounting, so delete those operations.

Change-Id: I7781773da86b26544f9389337bfc059d9483fef9
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/serialization/qcborvalue_p.h

@@ -101,6 +101,12 @@ class QCborContainerPrivate : public QSharedData
     ~QCborContainerPrivate();
 
 public:
+    QCborContainerPrivate() = default;
+    QCborContainerPrivate(const QCborContainerPrivate &) = default;
+    QCborContainerPrivate(QCborContainerPrivate &&) = default;
+    QCborContainerPrivate &operator=(const QCborContainerPrivate &) = delete;
+    QCborContainerPrivate &operator=(QCborContainerPrivate &&) = delete;
+
     enum ContainerDisposition { CopyContainer, MoveContainer };
 
     QByteArray::size_type usedData = 0;