repo-add: unconditionally create the database if it is missing
In f91fa546 (repo-add: do not recreate the database if nothing was changed),
repo-add was made to skip database write-out if there were no changes to
the database. However, this breaks the usage of repo-add to create a new
empty database: repo-add /path/to/mydb/mydb.db.tar.xz
.
Bring back support for this use-case by always writing the database if it is missing.
Fixes: f91fa546
Edited by Ivan Shapovalov