Have Jenkins use basebox:clean_old instead of basebox:clean_all

Originally created by @intrigeri on #12576 (Redmine)

See parent ticket for details.

Parent Task: tails#5630 (closed)

Related issues

• Related to tails#12002 (closed)
• Related to #14811 (closed)
• Blocked by #12595 (closed)
• Blocked by tails#12575 (closed)