The civix test command needs to connect to civi but looks for civicrm.settings.php instead of civicrm.settings.dist.php

The civix test command needs to connect to civi to run an extension test but looks for civicrm.settings.php in order to bootstrap instead of looking for the new file name civicrm.settings.dist.php.

The attached patch also changes the error message that the command gives when civicrm_api3_conf_path is not set:
Before: refers to parameters.yml
Patch: refers to civix config:set