update script should prompt for DB username, password

A recent post to the developer's group regarding other update.php changes inspired me to post this.

I found that my latest update only worked partially, because the database user for Drupal does not have ALTER permission. (I chose option 5 from the mysql_setpermission script). I could give the drupal user more permission, but I'm hesitant to do that for security reasons. So my request is that the update.php script prompt for an alternate username and password. If provided, the script would use that username and password rather than the defaults.

Next time I need to run the update script, I may be able to write a patch myself. If so, I'll post it here, but I'm not sure when I'll get around to it.

-Dave