Improve sql query to remove duplicates for roles stats

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

ee/app/models/ee/project_authorization.rb

@@ -5,7 +5,7 @@ module EE
     module ClassMethods
       def roles_stats
         connection.execute <<-EOF.strip_heredoc
-          SELECT CASE max(access_level)
+          SELECT CASE access_level
             WHEN 10 THEN 'guest'
             WHEN 20 THEN 'reporter'
             WHEN 30 THEN 'developer'
@@ -13,10 +13,14 @@ module EE
             WHEN 50 THEN 'owner'
             ELSE 'unknown' END
             AS kind,
-            count(DISTINCT user_id) AS amount
+            count(*) AS amount
+          FROM (
+              SELECT user_id, max(access_level) AS access_level
               FROM #{table_name}
+              GROUP BY user_id
+          ) access_per_user
           GROUP BY access_level
-          ORDER BY amount DESC;
+          ORDER BY access_level ASC;
         EOF
       end
     end