Allow messages about change renumbering, so cvs2p4 can be used
to import to an existing (nonvirginal!) server. Note that I
*don't* claim this works completely now, but from my
experience at Orca a year ago, this was the only bugaboo that
bit. Note also that it's still the user's obligation to insure
that there are no pathname overlaps with files that already
exist. *That* is guarenteed
not to work!