ci: bring back Coverity part 2

It's just a follow-up to https://github.com/systemd/systemd/pull/16266.

Currently the Coverity stage is failing with
```
Starting container systemd-fedora-latest
2db425228e1addbce607c7e47e492a0faef2c2c4e85701c6c239a50de95944eb
Error: No such container: bash
The command "$CI_MANAGERS/fedora.sh SETUP" failed and exited with 1 during .
Your build has been stopped.
```

https://travis-ci.org/github/systemd/systemd/builds/701798193