BUG-632: fix configuration interactions

This commit fixes various problems in configuration module code, so it
actually works. Key problems addressed:
- netty integration was not returning proper instance
- BGP/PCEP modules need to look at actual implementation mbean, not the
  service reference

Change-Id: Iaaf03a5fd94f4a2953f671015bee8f635a4c69d5
Signed-off-by: Robert Varga <rovarga@cisco.com>