CRM-13852 - avoid multiple calls to Array::value

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* CRM-13852: activity filter user preference: flush cache before setting
  http://issues.civicrm.org/jira/browse/CRM-13852
CRM-13852 - use php calls directly

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* CRM-13852: activity filter user preference: flush cache before setting
  http://issues.civicrm.org/jira/browse/CRM-13852
Merge pull request #2117 from dlobo/CRM-13852

CRM-13852 - avoid multiple calls to Array::value