remove: unused rpm repackaging support remnants
remove: unused rpmtrans internal _dopkgtup() helper
remove: unnecessary testing for prehistoric rpm versions in callback
Minimally teach dnf about rpm rpm >= 4.10 scriptlet start and stop callbacks

This is the same as yum commit b4195162200bc0fa918c25b75073e569dc9ddfa6
to make sure all scriptlet output gets logged (Related: RhBug:615763),
except dont bother testing for rpm version in the callback.