Code review comment for ~bryce/ubuntu/+source/fetchmail:fix-2035-hirsute

I've pushed latest changes, please re-review.

As mentioned in the last 2 comments, I'm opting to take the make check dependencies from Utkarsh's analysis, and opting to take Lucas' #1 suggestion (drop 'set -x'). With these changes, autopkgtest passes both inside a build container (via `sudo autopkgtest ./fetchmail_6.4.16-1ubuntu1.dsc -- null`) and externally with an ephemeral container (via `autopkgtest -U -s -o dep8-fetchmail ./fetchmail_6.4.16-1ubuntu1.dsc -- lxd images:ubuntu/hirsute/amd64`)

Thanks again!