content views - fix query that failed on older postresql

The query before this change worked ok for katello on F17; however,
on RHEL 6.3 it would generate the error below. It appears that the newer
version (9.1.7-1) of postgres is more lenient on the 'group by' than the older
version (8.4.13-1).

PGError: ERROR: column "content_views.name" must appear in the GROUP BY clause or be used in an aggregate function LINE 1: SELECT "content_views".* FROM "content_views" INNER JOIN "c... ^ : SELECT "content_views".* FROM "content_views" INNER JOIN "content_view_versions" ON "content_view_versions"."content_view_id" = "content_views"."id" INNER JOIN "content_view_version_environments" ON "content_view_versions"."id" = "content_view_version_environments"."content_view_version_id" INNER JOIN "environments" ON "environments"."id" = "content_view_version_environments"."environment_id" WHERE ("content_views".content_view_definition_id = 1) GROUP BY "content_views"."id" HAVING count("environments"."id") > 1 LIMIT 1 (ActiveRecord::StatementInvalid)

The new query provides an alternative that avoids using 'group by'
which, if used, would require us to list every column defined by
the content_views schema.