Revert "Revert broken Berksfile.lock"

This reverts commit 8599753228cd910e2f6ca8c75d862ff48fd96267.
Revert "Update path to Kafka log file in integration tests"

This reverts commit 7d80bd583e3295b39bdc11fa49d5bf3964079499.
Ignore Berksfile.lock

Mostly my fault for fucking up the partial revert, but I’ve about had
it with issues today, and there’s no real need to have this lock file
in the source tree.
Update path to Kafka log file in integration tests, properly

Never mind the idiot who apparently does not know how to use Git at all.
At least I didn’t force push master, yay me.