Bug 13098: Make _FixAccountForLostAndReturned refund the right thing

Bug 13098: Make _FixAccountForLostAndReturned refund the right thing

This patch changes the logic inside the method, to make it match the
behaviour described on the tests.

It uses the existing offsets on the account_offsets table to gather
information about the right things to refund.

To test:
- Run:
  $ kshell
 k$ prove t/db_dependent/Circulation.t
=> FAIL: Tests don't pass!
- Apply this patch
- Run
 k$ prove t/db_dependent/Circulation.t
=> SUCCESS: Tests pass!
- Sign off :-D

Followed test plan, patch works as described. All three patches pass QA
test tool
Signed-off-by: Alex Buckley <alexbuckley@catalyst.net.nz>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>