NO-JIRA: HA minor cleanup of qpid-ha tool

- Remove some dead code.
- Removed "set" command - not ready for production. All settings in qpidd.conf.
  - Removed related tests in ha_tests
- Improved help on promote command.
- Made option group for common broker connection options.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1589834 13f79535-47bb-0310-9956-ffa450edef68