When $Subject (we use the <chroot>/devel/ repositories), any build removal
removes unconditionally the build and it's result directory (e.g. 000012313-foo).
The devel/ repository receives "createrepo" action, though not the chroot
production directory (even though the repodata there might already reference
the very same build).

IMO we should do something like this:

1. auto createrepo enabled
2. some build is removed, we drop the build and run createrepo in main chroot
3. auto createrep is disabled, => we run full createrepo in /devel
4. some build is removed
   a) regenerate the chroot/repodata not currently done
   b) regenerate in chroot/devel/repodata
   c) we need to remove the build
5. auto createrepo re-enabled
   a) we run the full createrepo in main chroot dir
   b) we remove the devel/ repository, because nobody needs that and we should start over not currently done
6. some build is removed
   a) we can calmly just update the main chroot repodata