Add warning when fwupd fails because computer not on AC power
Submitted by Allen Welkie
Link to original bug (#787811)
Description
I tried to update my laptop's firmware using gnome-software. It failed silently, and I saw this in the journal:
22:53:49:0635 Gs failed to install com.dell.uefi5ffdbc0d.firmware: failed to prepare for update upower: Cannot install update when not on AC power
This should be shown in the gnome-software application. Possible duplicate of #709738