detect: allow rule errors to display error, but not be fatal

detect: allow rule errors to display error, but not be fatal

Add a new setup return code, -4 which will print the error, but not
error out in test mode. This is to support allowing incomplete hex, as
there is no context as to which rule had the issue.

For context:
- -3: error ok, no message
- -2: error not ok, no message
- -4: error ok, message