https://atomic.jira.com/browse/PION-1162
https://atomic.jira.com/browse/PION-1162

Keep GIL while releasing objects in session cache



acmorrow/pion-core,acmorrow/pion-core,acmorrow/pion-core,acmorrow/pion-core,acmorrow/pion-core,acmorrow/pion-core,acmorrow/pion-core