Ensure that ntp version is captured

On CentOS 7 `ntpd --version` is outputting:
```
ntpd 4.2.6p5

exit 0
```

However, the first line, with the version number is being outputted to STDERR and thus wasn't being captured.  This caused the Regexp.last_match to be empty which of course failed the cookbook.  This ensures everything is captured.