perf_data is not shown in attachment for Icinga2 OEC

Issue Summary

Icinga scripts are trying to create an image about the performance data, however since there is a mismatch between file names, this image cannot be seen in attachment.

Steps to Reproduce

https://github.com/opsgenie/oec-scripts/issues/10 

Expected Results

Performance data should be in attachment

Actual Results

Performance data is not in attachment

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available