Description of problem:
When shutdown  the system an updates are available, than gnome ask to install it on shutdown. But it automatic only works on none encrypted file systems, because it do it this order:
1. reboot
2. boot to update stage
3. install the updates
4. shutdown.

But on encrypted devices the automatic update fails at part 2, because the system needs an password.

An better solution can be:
1. switch to the update stage without reboot/unmount
2. install the updates
3. shutdown the system.

Version-Release number of selected component (if applicable):
gnome-shell-3.22.3-1.fc25.x86_64


How reproducible:
Every time updates are available on system shutdown. 

Steps to Reproduce:
1. mark "Install update on shutdown"

Actual results:
The automatic process fails, because at the reboot phase it will wait for the password.


Expected results:
That the updates can be installed on shutdown without unlock the encrypted device.

Additional info:
I think at the bug, there are more components involved.
Gnome, systemd, dnf etc.