Advice in failure message is out of date

[demeritcowboy]

Follow on to #624

If you try to r-run to see the message that was updated in that PR, you can't do it by having an incorrect civicrm_root as the message suggests. Probably that was true at one time but now if civicrm_root is wrong it doesn't even get this far to see the message, so the advice should be more on point about what failed.

I considered removing the entire reference to civicrm_root since it might lead them astray, but at least the main reason is stated now.

Drupal 8 has the same problem - see civicrm/civicrm-drupal-8#48

FYI @MikeyMJCO

[civibot]

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