Rest rolling upgrades, distributed -- new cluster can't load from old cluster properly

A try to mimic the process of REST Rolling Upgrades for one old and new server in a clustered environment failed.

Scenario is quite simple, we start 2 old servers, store some data in, start 2 new servers and point clients to that new cluster.
When issuing a get on a new cluster (want to fetch old entry from old store), the operation fails with attached stack trace.

I also include current ISPN testsuite where is added testRestRollingUpgradesDiffVersionsDist test as a reproducer.

Respective changes are mirrored in my remote branch: https://github.com/tsykora/infinispan/tree/ISPN-4330

You can run test like:

mvn clean verify -P suite.rolling.upgrades -Dzip.dist.old=/home/you/servers/previous-ispn-server-version.zip -Dtest=RestRollingUpgradesTest#testRestRollingUpgradesDiffVersionsDist