[collectd] collectd-nagios outputs performance data in floating point exponent form which is not allowed by nagios

[Lao Wai]

> So it seems that collectd-nagios does not conform to the specification required by nagios. Nagios extensions that parse performance data are therefore unable to parse the output from collectd-nagios when data is sufficiently large that it is printed in exponent form.
>
> It would be great if this could get fixed :)