This is the first stable release of the Drupal for Munin module which incorporates the needed changes to use Drush and no DB credentials in the script. Full list of changes:
Refactored to use only one script for all plugins.
Configuration:
After enabling the module copy the contents of admin/config/development/munin/script to /etc/munin/plugins/drupal, make it executable (chmod +x drupal) and restart munin-node service.
Start enabling plugins in admin/config/development/munin and check the graphs after 10-15 mins.