The reason for this change is to support the upcoming redis-cluster since
it has different behaviors compared to the client-side cluster implementation
provided by Predis. For example redis-cluster will not support key tags or
certain operations currently available with our client-side implementation.
The reason for this change is that not every cluster implementation can support
this behaviour, think of Redis cluster for example. We moved the implementation
of this method in Predis\Connection\PredisCluster since it can still be useful.