Merge pull request #550 from gao-yan/remove-unknown-conflicting-node

Fix: crmd: Remove unknown nodes with conflicting unames from CIB
Fix: crmd: Remove state of unknown nodes with conflicting unames from CIB
Fix: cluster: Remove unknown offline nodes with conflicting unames from node cache
Fix: attrd: Remove offline nodes from node cache
Fix: membership: Prevent use-after-free in reap_crm_member()