Related to work for 1138328. Wrap the new non-async uninv work for
storage node unlinking in a new Tx, like the other work done in that
method.  This may prevent an Oracle locking issue seen in test code cleanup
where we call both the sync and async uninventory in quick succession,
under potentially the same umbrella Tx.

(cherry picked from commit 1fc62b1044225f5cc48033de3783d19b1b047c9e)
Signed-off-by: Jay Shaughnessy <jshaughn@redhat.com>