core: Add config values for host kdump detection

Adds following to ConfigValues:

  FenceKdumpDestinationAddress
  FenceKdumpDestinationPort
  FenceKdumpMessageInterval
  FenceKdumpListenerTimeout
  KdumpStartedTimeout

All options can be changed using engine-config.

Change-Id: I4451719415958b21aa421105f4154db4afc755c0
Bug-Url: https://bugzilla.redhat.com/1079821
Signed-off-by: Martin Perina <mperina@redhat.com>