MFH: r544687

sysutils/auto-admin: Upgrade to 0.6.7 bugfix release

"date +%m" reports the month with a leading 0, which the shell interprets
as octal, causing auto-pkg-branch to fail in August and September.
This prevents auto-update-system from functioning properly with quarterly
snapshots.

Approved by: portmgr (blanket: bugfix)