Rename is_fence_kdump to is_pcs_fence_kdump
    
    Renames is_fence_kdump to is_pcs_fence_kdump to identify that this
    method should be used to detect fence_kdump configuration only in
    Pacemaker clusters.
    
    Bug-Url: https://bugzilla.redhat.com/1078134
    Signed-off-by: Martin Perina <mperina@redhat.com>
    Acked-by: Vivek Goyal <vgoyal@redhat.com>