SOAP auth fails on Drupal

When authenticating against SOAP on Drupal you get the following error

Using $this when not in object context

This error is triggered in CRM_Utils_System_Drupal::authenticate call line 469 due to this method being static now.

The solution is to replace code on line 469 with the following code

$cmsPath = $config->userSystem->cmsRootPath($realPath);

Code diff:
469c469
< $cmsPath = $config->userSystem->cmsRootPath($realPath);
—
> $cmsPath = $this->cmsRootPath($realPath);