CDB-3923 Fixes org user quota validation
CDB-3923 Expand org quota validation spec
CDB-3923 Fix rare case of user deletion surfaced by failing spec
CDB-3923 Fix OrganizationVisualization spec, which was failing after fixing quota validation for orgs
CDB-3923 Fix Relocator spec, which was failing after fixing quota validation for orgs
Merge pull request #720 from CartoDB/CDB-3923

CDB-3923 Fixes org user quota validation