BUG-650: clarify TransactionFactory close state handling

getAndSet() translates to a get() + compareAndSet(). We already know the
expected value, so we can skip the first bit. The nice thing is that CAS
will readily give us a boolean, so the code becomes a bit more clear,
too.

Change-Id: Id77dcefb7ba85512fcebbcae7f43f08cd8094fbc
Signed-off-by: Robert Varga <rovarga@cisco.com>
Merge "BUG-650: clarify TransactionFactory close state handling"