Fix path to grafana-cli in manifests/plugin.pp.

[go8ose]

On my Debian 8 system the grafana package has grafana-cli under /usr/sbin,
not /usr/bin. I don't have any experience with grafana, so I don't know if this is something that never worked, or if the grafana packaging has changed at some point.

[wyardley]

It's in /usr/sbin on the one system (CentOS 7) I checked too. But I don't think this fix is safe; at a minimum, should just set an explicit PATH for the exec (including both directories), and then reference the command without the full path in the cmd line.

But I think the better fix is to rework this to use types / providers; I'll take a stab at it.

[wyardley]

#63

[wyardley]

Thanks for the contribution; closing this one via #63, though.