Certificate ID isn't set for new nodes

Issue Summary

In signup_status_cert.module, when saving a new node, the signup_status_cert_nid isn't properly set, which results in a blank certificate when a user tries to access it.

The reason is that it is called during the "submit" operation in signup_status_cert_nodeapi(), which is called before the signup information for that node has been saved. If the signup_status_cert_nid is set during the "update" or "insert" operations, then it is saved properly.