Comment 9 for bug 1726803

Verified with shim-signed 1.37~18.04.3+15+1533136590.3beb971-0ubuntu1:
...
ubuntu@autopkgtest:/var/cache/apt/archives$ sudo rm /var/lib/shim-signed/mok/MOK.der
ubuntu@autopkgtest:/var/cache/apt/archives$ sudo update-secureboot-policy --new-key
Generating a new Secure Boot signing key:
Generating a 2048 bit RSA private key
...........................................................................................................+++
...................+++
writing new private key to '/var/lib/shim-signed/mok/MOK.priv'
-----
root@autopkgtest:/var/cache/apt/archives# echo /var/lib/dkms/zzz >> /var/lib/shim-signed/dkms-list
root@autopkgtest:/var/cache/apt/archives# env DEBIAN_FRONTEND=noninteractive update-secureboot-policy --enroll-key; echo $?
Running in non-interactive mode, doing nothing.
0
root@autopkgtest:/var/cache/apt/archives# cat > /var/lib/shim-signed/dkms-list <<EOF
> /var/lib/dkms
> /var/lib/dkms/nvidia-1
> /var/lib/dkms/r8168
> EOF
root@autopkgtest:/var/cache/apt/archives# mkdir /var/lib/dkms/nvidia
root@autopkgtest:/var/cache/apt/archives# env DEBIAN_FRONTEND=noninteractive update-secureboot-policy --enroll-key; echo $?
Running in non-interactive mode, doing nothing.
0
root@autopkgtest:/var/cache/apt/archives# cat > /var/lib/shim-signed/dkms-list <<EOF
> /var/lib/dkms
> /var/lib/dkms/r8168
> EOF
root@autopkgtest:/var/cache/apt/archives# env DEBIAN_FRONTEND=noninteractive update-secureboot-policy --enroll-key; echo $?
Running in non-interactive mode, doing nothing.
--- /var/lib/shim-signed/dkms-list 2018-11-06 17:47:43.490071095 +0100
+++ /var/lib/shim-signed/dkms-list.new 2018-11-06 17:47:43.490071095 +0100
@@ -1,2 +1,3 @@
 /var/lib/dkms
+/var/lib/dkms/nvidia
 /var/lib/dkms/r8168
1