SqliteTableModel: Notify view and parent class code when clearing cache

Call beginRemoveRows() and endRemoveRows() when emptying the cache. This
silences those warnings from QAbstractItemModel::endInsertRows() and
fixes a crash when exiting the program both ocurring when the data was
resorted.

src/sqlitetablemodel.cpp

@@ -58,7 +58,7 @@ void SqliteTableModel::setQuery(const QString& sQuery)
     sqlite3_finalize(stmt);
 
     // now fetch the first entries
-    m_data.clear();
+    clearCache();
     fetchData(0, m_chunkSize);
 
     emit layoutChanged();
@@ -282,3 +282,10 @@ void SqliteTableModel::updateFilter(int column, const QString& value)
     // Build the new query
     buildQuery();
 }
+
+void SqliteTableModel::clearCache()
+{
+    beginRemoveRows(QModelIndex(), 0, m_data.size()-1);
+    m_data.clear();
+    endRemoveRows();
+}

src/sqlitetablemodel.h

@@ -41,6 +41,7 @@ public slots:
 
 private:
     void fetchData(unsigned int from, unsigned to);
+    void clearCache();
 
     void buildQuery();