on restore, don't enable a target until its luns, etc are set up

sbp objects if you attempt to enable a target before its luns have
been configured.  This causes restoreconfig to fail.  Fix by setting
up luns first.

Signed-off-by: Jay Fenlason <fenlason@redhat.com>
Signed-off-by: Andy Grover <agrover@redhat.com>