cvsserver: Remove trailing "\n" from commithash in checkin function

The commithash for updating the ref is obtained from a call to
git-commit-tree.  However, it was returned (and stored) with the
trailing newline.  This meant that the later call to git-update-ref that
was trying to update to $commithash was including the newline in the
parameter - obviously that hash would never exist, and so git-update-ref
would always fail.

The solution is to chomp() the commithash as soon as it is returned by
git-commit-tree.

Signed-off-by: Andy Parkins <andyparkins@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-cvsserver.perl

@@ -1152,6 +1152,7 @@ sub req_ci
     close $msg_fh;
 
     my $commithash = `git-commit-tree $treehash -p $parenthash < $msg_filename`;
+    chomp($commithash);
     $log->info("Commit hash : $commithash");
 
     unless ( $commithash =~ /[a-zA-Z0-9]{40}/ )