-- worked and fixed for CRM-13088

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* CRM-13088: civicrm_contribution_product schema inconsistent in fresh installs vs upgrades
  http://issues.civicrm.org/jira/browse/CRM-13088
-- added missed constraint, fixed for CRM-13088

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* CRM-13088: civicrm_contribution_product schema inconsistent in fresh installs vs upgrades
  http://issues.civicrm.org/jira/browse/CRM-13088
Merge pull request #1414 from pradpnayak/CRM-13088

-- worked and fixed for CRM-13088
Tested 4.2.9 -> 4.3.6 upgrade. Constraint is present.