LP#1257915: add live_t tests

LP#1257915: add live_t tests

And here's a test plan for humans:

[1] Create a purchase order with, say, 3 lineitems and 2
    copies on each of these.
[2] Receive the first two lineitems outright.
[3] Receive one of the copies on the last lineitem and cancel
    the other with a cancellation reason that's permanent (e.g.,
    bad ISBN) rather than temporary (e.g., backordered).
[4] Note that the purchase order's state remains 'on-order'
[5] Apply the patch.
[6] Repeat steps #1-4. This time, the PO's state should be
    'received'.
[7] Repeat steps #1-4, but this time, choose backordered as
    the cancellation reason. This time, the PO's state should
    remain 'on-order'.

It should be noted that the patches for this bug do *not*
retrospectively mark purchase orders as being received.

Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>