swift-object-expirer systemd file uses legacy config file

[Andy Foster]

According to this https://docs.openstack.org/swift/victoria/overview_expiring_objects.html we should no longer be using the separate config file object-expirer.conf for swift-object-expirer, and should instead put a section in object-server.conf.

The swift-init script correctly uses the object-server.conf file when starting the object-expirer. But the systemd unit still uses the legacy config.

# systemctl cat swift-object-expirer
# /lib/systemd/system/swift-object-expirer.service
[Unit]
Description=OpenStack Swift object expirer
ConditionFileNotEmpty=/etc/swift/object-expirer.conf
AssertFileNotEmpty=/etc/swift/account.ring.gz
AssertFileNotEmpty=/etc/swift/container.ring.gz
AssertPathExistsGlob=/etc/swift/object*.ring.gz
Documentation=man:swift-object-expirer(1)

[Service]
User=swift
Group=swift
CacheDirectory=swift
RuntimeDirectory=swift lock/swift
ExecStart=/usr/bin/swift-object-expirer /etc/swift/object-expirer.conf
Restart=on-failure
LimitNOFILE=65535

[Install]
WantedBy=multi-user.target