```
net-mgmt/prometheus2: Fix a path in pkg-plist.
Fix the following installation phase error:
cp: /usr/local/etc/newsyslog.conf.d/prometheus.conf: No such file or directory
It was caused by a relative path being specified in pkg-plist instead of an
absolute one (a leading "/" was missing).
Sponsored by: Bally Wulff Games & Entertainment GmbH
```