Should only add CCK fields to followup form, not issue form.

Currently, there's code in issue.inc to manually add the CCK fields associated with the project_issue content type into the issue form. This is shared by both initial issue creation, and the followup form. Unfortunately, it's all buggy and broken for the initial issue form, since a) the node_load() it tries to do always fails, and b) it's duplicate, since CCK is already adding those form elements to the initial issue node form.

To reproduce the bug:
a) start with an unpatched HEAD version of project*.
b) install content.module and some field modules.
c) define a field and attach it to the project-issue content type.
d) try to create an issue.

So, I just moved the CCK-specific code block out of issue.inc's project_issue_form() into comment.inc's project_comment_form(). This is *only* used for the follow-up form, which is the only place we want the fields manually added. Tested and it seems to work fine and remove all the crazy warnings I was getting, but another review and more testing would be nice.