The `CONFIGS.write(GLANCE_SWIFT_CONF)` is missing in the object-store
hook. This config file is used when the `swift` backend is enabled.
This bug is only encountered on some deployments, because there are multiple
places where `CONFIGS.write_all()` is called.
If the `object-store` relation is established, and another hook calls
`CONFIGS.write_all()`, this problem wouldn't reproduce. However, if
`object-store` relation is executed last, this issue will pop up.
Closes-Bug: #1915300
Change-Id: Ie52b18fc4dc637dbeec5ecfb8d5930a24c5f72cf