strip extra space for column name

[mutantsan]

If we have an extra space after truncating the column name, the validation from this function will fail:

def is_valid_field_name(name: str):
    '''
    Check that field name is valid:
    * can't start or end with whitespace characters
    * can't start with underscore
    * can't contain double quote (")
    * can't be empty
    '''
    return (name and name == name.strip() and
            not name.startswith('_') and
            '"' not in name)

I'm adding an extra strip to ensure, that the column name doesn't end with whitespace after truncating.