Fixed #10182 -- Corrected realiasing and the process of evaluating values()...

Fixed #10182 -- Corrected realiasing and the process of evaluating values() for queries with aggregate clauses. This means that aggregate queries can now be used as subqueries (such as in an __in clause). Thanks to omat for the report.

This involves a slight change to the interaction of annotate() and values() clauses that specify a list of columns. See the docs for details.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@9888 bcc190cf-cafb-0310-a4f2-bffc1f526a37