High: Fencing: Overhaul the fencing daemon

• Allow metadata queries via the admin tool even if stonith-ng isnt running
• Support per-victim values to be sent to stonith devices during resets
• Have the executioner perform a broadcast notification (to be recorded and relayed to clients by any active peers)

Mercurial revision: 92e880a58e418e91635bcd7fbec4d838a8a084e8