Now that we have a bit more control, let's convert our object into
a lockable object and let that magic handle the create and lock/unlock.

This also involves creating a virNodeDeviceEndAPI in order to handle
the object cleanup for API's that use the Add or Find API's in order
to get a locked/reffed object. The EndAPI will unlock and unref the
object returning NULL to indicate to the caller to not use the obj.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>