Bug fix---removed unnecessary assert()

The condition was checked for anyway.
Bug fix---cb_cond_blog_title()

cb_cond_blog_title() was being given a struct callback_data, not a List (but
that was okay because the first element of a struct callback_data *is* a
list), but it wasn't checking to see if entry was valid---it just assumed it
was.  The assert that was there was triggering.  Removed to an actual test.

The entry is not valid if you give an entry that doesn't exist.
Beefed up a conditional check.

The check to see if we have a valid entry should be

	NodeValid(&entry->node) && entry->valid

instead of just

	entry->valid

Could give a false positive at some point.