I understand this happened with Drush 9 but we can handle this for lower Drus...

I understand this happened with Drush 9 but we can handle this for lower Drush versions as well. I tested this since Drush 7 and the constant 'DRUSH_DRUPAL_ROOT' returns the same thing. The attached patch changes the constant in all the locations I found this used. I tested this on a site with Drush 9 and Drush 8.1.2 and both generate the same report.

In any case, I think the error should be handled in a better way. If you want to support previous versions of Drush (which may be supported by this patch but I couldn't test), then we can just test for both constants and check if $handle is valid (we should be doing that anyway). Thoughts please?