We have been getting a lot of cvs log failures recently on
deadlock.netbeans.org, I think caused by there being many updated files in one
build.

1. Hudson does not report any actual error output from CVS, just that it "failed
with exit code 255". (Ant's ChangeLogTask seems to capture all output even if
the command failed, which is perhaps a bug in Ant.) This is not very helpful,
but I suspect that it is a max command length limitation.

2. Currently Hudson limits the max number of arguments on Windows only,
otherwise defaulting to logging the whole working dir (which for a big project
is unacceptably slow, but at least it works). For Unix, there is no limit.
Probably there should be some (I hope rather higher) limit.

3. Another option is to check if the log task fails when using an explicit list
of arguments, and if so, automatically retry by logging the whole working dir.
Then we could discard the hardcoded max arg limit.