Tag list user docs

Hi Boone-

This pull is in response to issue #379. I found that the select statement that builds the tag list was kind of weird on the user docs list. I made two query_arg changes that have cleared the problem up for me. After these changes, the select statements looked like this:

```
Started by me:
SELECT   wp_posts.* FROM wp_posts  WHERE 1=1  AND wp_posts.post_author IN (1)  AND wp_posts.post_type = 'bp_doc' AND (wp_posts.post_status = 'publish' OR wp_posts.post_status = 'trash')  ORDER BY wp_posts.post_date DESC

Edited by me:
SELECT   wp_posts.* FROM wp_posts  WHERE 1=1  AND wp_posts.ID IN (19001,18655,18653,15575,15230,15135,15131) AND wp_posts.post_type = 'bp_doc' AND (wp_posts.post_status = 'publish')  ORDER BY wp_posts.post_date DESC
```

And the tag list and doc list match. Thanks again for working on bp-docs.