CRM-14025 committing PR-2247 to 4.4 branch as intended.

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* CRM-14025: Manage registration pages don't call postProcess hook
  http://issues.civicrm.org/jira/browse/CRM-14025
Merge pull request #2250 from davecivicrm/CRM-14025

CRM-14025 committing PR-2247 to 4.4 branch as intended.
CRM_Core_Session - allow empty string in setStatus