Form submission handler for path_admin_form().
path_admin_form_delete_submit()
function path_admin_form_submit($form, &$form_state) {
// Remove unnecessary values.
form_state_values_clean($form_state);
path_save($form_state['values']);
drupal_set_message(t('The alias has been saved.'));
$form_state['redirect'] = 'admin/config/search/path';
}