core: Suppress kdump not configured warning when PM is off

Suppresses displaying warning "Kdump integration is enabled for host
'dev-21', but kdump is not configured properly on host." when host
become Up and its power management is turned off.

Change-Id: I8989c83bf7b9c08bd839c81c30f6f1b0edf31322
Bug-Url: https://bugzilla.redhat.com/1125206
Signed-off-by: Martin Perina <mperina@redhat.com>