CRM-21179 - Case.gettypestats - Fix loading of average_duration for "My cases"
CRM-21179 - Case.gettypestats - Fix loading of average_duration for "My cases"

civicrm/org.civicrm.civicase,civicrm/org.civicrm.civicase,civicrm/org.civicrm.civicase