NO-JIRA: Clean up excessive "notice" level log messages, add start-up/shut-down messages.

- Demote excessive "notice" level log messages to "info"
- Provide clear notice "start-up/shut-down" messages at start and end of broker log.
- Log broker PID in start-up/shut-down messages.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1617293 13f79535-47bb-0310-9956-ffa450edef68