With this patch free_device is now used to free what is allocated in the
alloc_device callback and destroy_device tears down the resources that are
setup in the configure_device callback.

This patch will be needed in the next patch where tcmu needs
to be able to look up the device in the destroy callback.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NBart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>