perl-modules 5.20.2-6 should not be in our time-based snapshots for Stretch and sid

reprepro-time-based-snapshots@apt:~/repositories/debian$ reprepro ls perl-modules perl-modules | 5.20.2-3+deb8u4 | jessie | amd64, i386 perl-modules | 5.20.2-3+deb8u5 | jessie-proposed-updates | amd64, i386 perl-modules | 5.20.2-6 | stretch | amd64, i386 perl-modules | 5.20.2-6 | sid | amd64, i386

… while this package was removed from Stretch.

Parent Task: #5926 (closed)

Original created by @intrigeri on 11496 (Redmine)