nodedev: fix mdev add udev event data handling

nodedev: fix mdev add udev event data handling

Two situations will trigger an udev add event:
 1) the mdev is created when started (transient) or
 2) the mdev was defined and is started
In case 1 there is no node object existing and no config data is copied.
In case 2 copying the active config data of an existing node object will
only copy invalid data. Instead copying the defined config data will
store valid data into the newly added node object.

Signed-off-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Reviewed-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Marc Hartmayer <mhartmay@linux.ibm.com>