Fix number of replies for draft comments on /showreview

The internal number includes the initial comment, while the displayed
number should only include additional comments (i.e. replies.)  The
internal number also doesn't include any draft comments, not even those
by the user loading the page.  When combined, this leads to an internal
number of comments of zero for draft comments, which was adjusted to
minus one (to avoid counting the initial comment as a reply.)

To avoid displaying "-1 reply", display any internal number less than two
as "No replies".