[BUG] Metric backmon_backup_file_young_count reports incorrectly

[thomashoell]

Given the following definitions file

'./pfsense-backup':
  defaults:
    schedule: 05 04 * * *
    purge: false
  files:
    '%Y%M%D-config.xml':
      alias: pfSense
      retention-count: 14
      retention-age: 14d
'./freeipa-backup/{{date}}':
  fuse:
    - 'date'
  defaults:
    schedule: 30 21 * * *
    purge: false
  files:
    'header':
      retention-count: 14
      retention-age: 14d
    'ipa-full.tar':
      retention-count: 14
      retention-age: 14d

Backmon reports the following metrics:

# HELP backmon_backup_file_young_count The amount of backup files in this group that are younger than the maximum age (file_age_aim_seconds).
# TYPE backmon_backup_file_young_count gauge
backmon_backup_file_young_count{dir="./freeipa-backup/{{date}}",disk="ws3-backup",file="header",group="freeipa-backup/{{date}}"} 0
backmon_backup_file_young_count{dir="./freeipa-backup/{{date}}",disk="ws3-backup",file="ipa-full.tar",group="freeipa-backup/{{date}}"} 0
backmon_backup_file_young_count{dir="./pfsense-backup",disk="ws3-backup",file="pfSense",group="pfsense-backup"} 0

However, since retention-age is set, the metric should report properly (value 0 for each metric is probably wrong).