Fix sip errors

python/core/qgsdataitemproviderregistry.sip

@@ -48,6 +48,8 @@ Add a provider implementation. Takes ownership of the object.
 Remove provider implementation from the list (provider object is deleted)
 %End
 
+  private:
+    QgsDataItemProviderRegistry( const QgsDataItemProviderRegistry &rh );
 };
 
 /************************************************************************

python/core/qgsexpressionfieldbuffer.sip

@@ -84,9 +84,9 @@ class QgsExpressionFieldBuffer
  \param flds The fields to be updated
 %End
 
-    QList<ExpressionField> expressions() const;
+    QList<QgsExpressionFieldBuffer::ExpressionField> expressions() const;
 %Docstring
- :rtype: list of ExpressionField
+ :rtype: list of QgsExpressionFieldBuffer.ExpressionField
 %End
 
 };

src/core/qgsdataitemproviderregistry.h

@@ -55,6 +55,9 @@ class CORE_EXPORT QgsDataItemProviderRegistry
     void removeProvider( QgsDataItemProvider *provider );
 
   private:
+#ifdef SIP_RUN
+    QgsDataItemProviderRegistry( const QgsDataItemProviderRegistry &rh );
+#endif
 
     //! available providers. this class owns the pointers
     QList<QgsDataItemProvider *> mProviders;

src/core/qgsexpressionfieldbuffer.h

@@ -99,7 +99,7 @@ class CORE_EXPORT QgsExpressionFieldBuffer
      */
     void updateFields( QgsFields &flds );
 
-    QList<ExpressionField> expressions() const { return mExpressions; }
+    QList<QgsExpressionFieldBuffer::ExpressionField> expressions() const { return mExpressions; }
 
   private:
     QList<ExpressionField> mExpressions;