Clustering : Ensure that all logging at debug level is done conditionally

This is required for performance reasons.

Basically instead of simply doing.

LOG.debug("Foo {}", bigcalc());

do

if(LOG.isDebugEnabled()){
LOG.debug("Foo {}", bigcalc());
}

This bug applies to code in,

sal-clustering-commons
sal-akka-raft
sal-distributed-datastore