Bug#870121: mate-power-manager: sometimes hits not-reached assertion on startup

[James Lu]

Control: retitle -1 mate-power-manager: crashes with upower 0.99.5 on any device with a backlit keyboard
Control: severity -1 grave
Justification: renders package unusable on a large range of systems

Hi everyone,

According to the upstream issue, mate-power-manager is now completely broken with upower
0.99.5 on any device with a backlit keyboard. This makes it effectively unusable on a wide
slew of devices, so I'm bumping the severity to make the issue more notable.

Best,
James