git-cvsserver: run post-update hook *after* update.

CVS server was running the hook before the update action was actually done. This performs the update before the hook is called. The original commit that introduced the current incorrect behavior was 394d66d "git-cvsserver runs hooks/post-update". The error in ordering of the hook call appears to have gone unnoticed, but since git-cvsserver is supposed to emulate receive-pack, it stands to reason that the hook should be run *after* the update. Since this behavior is inconsistent with recieve-pack, users are either: 1) not using post-update hooks with git-cvsserver; 2) using post-update hooks that don't care whether they are called before or after the actual update occurs; 3) using post-update hooks *only* with git-cvsserver, and relying on the hook being called just before the update. This patch would affect only users in case 3. These users are depending on fairly obviously wrong behavior, and moreover they can simply change their current post-update into post-recieve hooks, and their systems will work correctly again. Signed-off-by: Stefan Karpinski <stefan.karpinski@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>