ci: Install upower to work-around tracker warning

And start a system bus to host it.

(tracker-miner-fs-3:2068): libupower-glib-WARNING **: 15:25:58.429: Couldn't connect to proxy: Could not connect: No such file or directory
(tracker-miner-fs-3:2068): Tracker-WARNING **: 15:25:58.429: Unable to connect to UPower
2 jobs for master in 3 minutes and 29 seconds
Status Job ID Name Coverage
  Test
passed build_stable #965540

00:03:29

passed build_tracker2 #965541

00:03:26