Support for RH-SSO upgrade with zero downtime (rolling upgrades)

Issue

• Upgrade / update with zero downtime / maintaining availability for existing clients
• Rolling upgrade with zero downtime

• Using Rolling deployment strategy results in the below error:

  01:40:03,870 ERROR [org.jgroups.protocols.TCP] (TransferQueueBundler,ejb,sso-prod-6-cgwdd) JGRP000029: sso-prod-6-cgwdd: failed sending message to sso-prod-5-4nhfv (66 bytes): java.net.SocketTimeoutException: connect timed out, headers: GMS: GmsHeader[VIEW_ACK], UNICAST3: DATA, seqno=76, TP: [cluster_name=ejb]
  

  Or

  11:17:10,918 WARN  [org.jgroups.protocols.TCP] (TcpServer.Acceptor [7600],null,null) JGRP000006: failed accepting connection from peer: java.io.IOException: packet from /172.25.54.122:39709 has different version (4.0.20) from ours (3.6.13); discarding it