Bug#1108278: shim-signed: Asks to disable EFI Secure Boot with enrolled DKMS key

[Jesse Rhodes]

If update-secureboot-policy can query mokutil to check if secure boot is 
enabled, then it can also query mokutil to check if the key from 
/var/lib/dkms/mok.pub is enrolled. This popup should never appear on a 
system with secure boot configured correctly with dkms.

sney