from_disk: Do not drop tags with missing tagger or date
Old versions of Git didn't writer them, eg. see tags refs/tags/v2.6.11 to refs/tags/v2.6.13-rc3 in linux.git
Migrated from D6069 (view on Phabricator)
Old versions of Git didn't writer them, eg. see tags refs/tags/v2.6.11 to refs/tags/v2.6.13-rc3 in linux.git
Migrated from D6069 (view on Phabricator)