Group by doesn't work when is only applied in a filter

This is a follow up of: #652812: get_count_optimized & has_aggregate undefined in views_plugin_query_default.inc

I wrote another test that fails. The problem is that 652812 only check if has_aggregate is setted to TRUE when fields are analysed, however in views that doesn't display COUNT, SUM, MAX, etc in the SELECT statement like this simple query:

SELECT type 
FROM node 
GROUP BY type
HAVING COUNT(nid) > 3

GROUP BY and HAVING are not added.

Patch with the new GROUP BY test and patch to fix this bug are attached.