Protect against a failure from hook_taxonomy_term_insert() in pathauto

I added this as an issue a few days ago (see https://www.drupal.org/node/2396373) and thought perhaps a pull request would be easier than a patch. termCreate() runs taxonomy hooks that, when pathauto has group-specific paths defined, causes a fatal error if DRUPAL_ROOT != getcwd().

I'm loving behat and the drupal-extension - thank you!