upgrade: drop support for old style optimization names
Old style optimization names like redeltaparent were converted into
re-delta-parent more than two years ago. The old names were kept around for
sometime because of BC reasons.
Refer 5608b5a6c3231c4ec771171cc3079142c7672be6. The commit states the map is
there for a while and we can drop them as the underlying command is a debug
Differential Revision: https://phab.mercurial-scm.org/D9614