Start and end Date in views argument comparison incorrect

Problem

When comparing both start and end values with the use_fromto in date_views_argument_handler_simple

The following SQL is generated:

(DATE_FORMAT(field_data_field_date.field_date_value2, '%Y-%m') >= '2017-08' AND DATE_FORMAT(field_data_field_date.field_date_value, '%Y-%m') <= '2017-08')

With this code:

$this->query->add_where_expression($group, "$field_max >= $view_min_placeholder AND $field_min <= $view_max_placeholder", array($view_min_placeholder => $view_min, $view_max_placeholder => $view_max));

Proposal

(DATE_FORMAT(field_data_field_date.field_date_value, '%Y-%m') >= '2017-08' AND DATE_FORMAT(field_data_field_date.field_date_value2, '%Y-%m') <= '2017-08') )

$this->query->add_where_expression($group, "$field_min >= $view_min_placeholder AND $field_max <= $view_max_placeholder", array($view_min_placeholder => $view_min, $view_max_placeholder => $view_max));