security/sudo: fix packaging with PYTHON option enabled (+)

This a followup to commit 3ee710e0b22309a7e87c71b87bf5510aa8678ed8

sudo-1.9.11 have moved plugins manpages from section 8 to section 5

Pointy hat to: cy
Approved by: portmgr blanket

(cherry picked from commit 39c8b4fa2e8fc9df650ab9863761c637898a0bbb)