Fix coverity uninitialized members warnings

Author: nyalldawson

src/providers/ogr/qgsogrdbtablemodel.h

@@ -54,7 +54,7 @@ class QgsOgrDbTableModel : public QStandardItemModel
 
   private:
     //! Number of tables in the model
-    int mTableCount;
+    int mTableCount = 0;
     QString mPath;
 
     QIcon iconForType( QgsWkbTypes::Type type ) const;

src/providers/wms/qgsxyzconnection.h

@@ -32,7 +32,7 @@ struct QgsXyzConnection
   QString password;
   // Referer
   QString referer;
-  bool hidden;
+  bool hidden = false;
 
   QString encodedUri() const;
 };
@@ -55,4 +55,4 @@ class QgsXyzConnectionUtils
 };
 
 
-#endif // QGSXYZCONNECTION_H
+#endif // QGSXYZCONNECTION_H