Added handler for PRAGMA foreign_key_list in sqlite dialect

This addition should fix issues with getting foreign keys from a sqlite database
```javascript
sequelize.query(self.queryInterface.QueryGenerator.getForeignKeysQuery(tableName, self.sequelize.config.database))
```
Maybe the preceding lines could be rewritten instead?
```javascript
                   } else if (self.sql.indexOf('PRAGMA foreign_key') !== -1) {
                     result = results;
```