kdump: Add kdump plugin

Adds kdump plugin to install kexec-tools package and configure
fence_kdump to enable kdump detection for the host in engine.

Change-Id: Idda48cb053c7e8747de5434c3681403f739c06b1
Bug-Url: https://bugzilla.redhat.com/1079821
Signed-off-by: Martin Perina <mperina@redhat.com>