[PATCH] convert: fix cvsnt mergepoint referring synthetic parent

[Greg Ward]

Progress!  With the patch I just sent
("test-convert-cvsnt-mergepoints: ignore differences between CVS 1.11
and 1.12"), the test now behaves the same under CVS 1.11 and 1.12.

On the slow PowerMac running NetBSD and CVS 1.11, it now passes 10/10 times.

On the fast Xeon server with CVS 1.11, it still fails 10/10 times ...
but the failure is similar to the intermittent failures I'm seeing
with CVS 1.12 on medium-speed hardware.  That is, CVS ignores one of
the early commit commands, causing havoc.

Greg