Improve logic for determining overall update status

Thanks for adding the update status checks --- this is really cool.

For the sites I've tested on so far, the module data is properly conveyed from individual sites to the aggregator, and the aggregator properly shows individual module update statuses.

However, in the overview table, the "Updates" column doesn't seem to be calculated correctly --- for sites that are fully up-to-date, it's reporting "Available" (updates column = 2).

In prod_monitor.update.inc, you have this code:

          if (empty($release['version_extra']) && $patch == $release['version_patch']) {
            $available[$project]['recommended'] = $version_patch_changed;
            // We have at least one new update, only set if there are no
            // security updates yet.
            if ($modules->updates < 2) {
              $modules->updates = 2;
            }
          }

...but I believe the first conditional in the above snippet will be true in cases other than just when an update is available (i.e., when the installed patch version is equal to the latest-available patch version).

Could we instead check the final status, after that whole gigantic mess is finished? I've attached a patch to do that, which works so far on my production monitor.