[API] Fix off-by-one in active LB count

There is an active LB count that says how many LBs should be on a device prior
to freeing it.  Before this should have been 0, after moving one of the
delete queries this should now be 1.

Change-Id: I09d6deec9a4a098d0371806444f69e5746f9a2a8
[API] Fix race condition in DELETE

If a device has both LBs deleted simultaneously a race leaves one behind

Change-Id: If583aff33a349bedcfb302c657f8392f1d360749