Revert "netstat: Resolve duplicate "dropped-packets" key from libxo output"

This reverts commit 94567c8641e235763b5b2926416d89d36654cde1.

This breaks normal netstat output. It's kinda tricky to do a quick fix
on, so revert this until that can be fixed. If via github, please
open a new pull request...

Sponsored by: Netflix
Pull Request: https://github.com/freebsd/freebsd-src/pull/1331