core: make message ovf store specific

Changed ACTION_TYPE_FAILED__DISK_NOT_IN_APPLICABLE_STATUS to be specific
to OVF disks to make it clearer.

Change-Id: Ie29c226f76839863008b25c69d4923c9685b17f7
Bug-Url: https://bugzilla.redhat.com/1114431
Signed-off-by: Liron Aravot <laravot@redhat.com>