tests/access: make test a little safer

so the test fails nicely, instead of with a:

````
TypeError: Cannot read property 'fail' of undefined
    at Object.<anonymous> (/Users/matt/Documents/git/haraka/tests/plugins/access.js:277:58)
    at Plugin.exports.helo_access (access:261:42)
    at Object.exports.helo_access.blacklisted regex (/Users/matt/Documents/git/haraka/tests/plugins/access.js:282:21)
````