RPC-LIB: Change to prevent NullPointerException

when polling for AuditMessages from RPC (on RPC re-deployment)
LDAPC: fixed error message

- When processing of some AuditMessage fails, pass message ID
  to exception text in logs, not message itself.
Merge pull request #408 from zlamalp/rpclib

RPC-LIB: Change to prevent NullPointerException