Comment 1 for bug 1577926

underlying bug was not apt-related, but could be worked around by deleting the _apt user - apt will then do exactly the same thing as I successfully tested on console.

to spare future users some pain in debugging such, I recommend
- adding getpwuid(geteuid()) to the relevant error and debug messages
- referencing the existence of Debug::Acquire::gpgv in apt-key(8) or apt-secure(8)
sorry, I am not qualified to build these into a proper patch.