Backup: duplicity doesn't cleanup old backups

[gsanchietti]

After implementation of #5691 the duplicity backend doesn't cleanup old backup anymore.

Steps to reproduce

• Configure a backup using duplicity engine
• Configure the retention period

Expected behavior

Old backups are removed after the retention period.

Actual behavior

Backups are not removed, and /var/log/messages contains output similar to:

Deleting local /var/lib/nethserver/backup/duplicity/backup-data/15804d01e2cefd32869f1fbbbbb9611c/duplicity-full-signatures.20190127T032410Z.sigtar.gz (not authori
tative at backend).

Components

nethserver-backup-data-1.5.0-1.ns7.noarch

[nethbot]

in 7.6.1810/testing:

• nethserver-backup-data-1.5.0-1.3.gdb9e909.ns7.noarch.rpm x86_64 armhfp aarch64

[gsanchietti]

Test case
Check the bug is not reproducible

[dnutan]

Test case OK. No more 'not authoritative' error message and cleanup of old backups succeeds.
Not sure it is related but before applying the patched version was getting this error (to be monitored if happens at next backup):

Error opening: /var/cache/restore/duc.db - Database version mismatch

[gsanchietti]

Thank you @dnutan for the effort!
Reported problem it's not related, but could be another bug.
If the error persists, delete the file and let duc recreate it on next run.

[nethbot]

in 7.6.1810/testing:

• nethserver-backup-data-1.5.0-1.4.g739c799.ns7.noarch.rpm x86_64 armhfp aarch64

[nethbot]

in 7.6.1810/testing:

• nethserver-backup-data-1.5.0-1.5.g4b43946.ns7.noarch.rpm x86_64 armhfp aarch64

[nrauso]

Tested: OK