Change to follow NSQAdmin method for deleting to properly handle lookupd & nsqd.

Previous version only deleted in nsqd, didn't call delete on lookupd first as the NSQD Admin tool does. Updated to follow the same process found there.

@gjohnson this bud's for you.
No need for `NODE_PATH`, lets just do:

```
test:
  @./node_modules/.bin/mocha --require should --recursive tests
```