Rework master startup/shutdown/failover

This (big) patch reworks the master startup/shutdown and the fixes the
master failover.

What does the patch do?

For master start/stop:
  - remove the old ganeti-master script and its associated man page
  - moves the ip start/stop directly into the backend.(Start|Stop)Master
  - adds start/stop of the master/rapi daemon into these functions,
    selectively based on the start/stop arguments
  - makes the master call via rpc StartMaster(start_daemons=False) to
    the local node so that the master IP is started
  - and finally changes the example init.d script to directly start and
    stop all three daemons, since they do the right thing (depending on
    master/not master role)

For master failover:
  - moves the code from LUMasterFailover into bootstrap.MasterFailover,
    since we need to start/stop the master during this operation and
    thus it can't be executed from the master
  - removes the LUMasterFailover and its associated opcode

Notes: ubuntu's /etc/lsb-base-logging.sh is dumb, so the messages 'not
master' are not seen during startup on non-master nodes.

Reviewed-by: ultrotter