merge: drop special parent assignment in the obsolete case We can safely drop this because the very same assignment is enforcement later in the function. Dropping it will make it simpler to extract the default destination logic in its own function.

bundle: use bundle2 if repository uses general delta As bundle1 does not support generaldelta, this would mean recomputing delta at bundle time. This is similar to what we do for strip and shelve and was tracked as issue4865.

parsebundletype: add a comment for future generation