The cvs postinstall runs /sbin/install-info on the two files /usr/info/cvs.info.gz and /usr/info/cvsclient.info.gz. However, those files don't exist; they're actually (well, presumably) the files cvs.info-1.gz and cvsclient.info-1.gz instead. This would matter more if install-info appeared to look at them at all, but it doesn't.
Whoops, pilot error; there are indeed cvs.info.gz and cvsclient.info.gz files there as well as the info-1 files. I probably got mislead and missed seeing them during my attempt to track down why they aren't appearing in the top-level info menu (which is, I think, a generic bug in the install-info program). However: install-info says that none of the cvsclient info files have an info dir entry. This may make the install-info invocation on cvsclient.info.gz fail (once install-info gets fixed so that it should normally succeed).
You are right, install-info doesn't seem to be working. As nearly as I could tell, the --entry option to install-info doesn't work. So the fix will be to make sure that cvs.info and cvsclient.info have info-dir entries (I've submitted a fix to cvsclient.info and put it on http://people.redhat.com/kingdon/), and edit the cvs.spec file to not use --entry. I'm assigning this bug to me so I remember to do it :-).
the gnome help program can find the cvs info files, but typing invo cvs just brings up the man page. i suppose the actual existence on info pages, and not man pages, can't be considered a bug? i hate info. anyway, i was just going to mention the cvs info not working thing, but since you folks have found it already i'll just add this rambling note instead...
Fixed in the current tree