db: make the --repositories-file change more announced

Document the version when changed. And print error with similar note
if the given repositories-file cannot be read.
2 jobs for master in 40 seconds
Status Job ID Name Coverage
  Test
passed #223103
x86_64 docker-alpine
test:alpine

00:00:34

passed #223104
x86_64 docker-alpine
test:debian

00:00:39