Raft behavior logging

Raft behavior logging

Added more logging in the raft behavior classes where appropriate.

Reduced logging in some places to trace or removed redundant logging to
avoid too much output when debug level is enabled.

Removed isDebugEnabled() checks in various places where not needed to
improve test line coverage.

Also I found it useful to see the behavior's state in the log messages.
So I added a logName field and method to AbstractRaftBehavior that
is printed in each log message instead of just context.getId().

Also added/modified toString() in a few RaftRPC message classes.

Change-Id: Ic4d3c93e25d5caf16319b8433d54cab69b26f5c0
Signed-off-by: tpantelis <tpanteli@brocade.com>