Bug 27064: Correct transferbook.t tests to reflect new behaviour of transferbook()

Bug 27064: Correct transferbook.t tests to reflect new behaviour of transferbook()

The transferbook() behaviour was changed so that it only allows
transferring the item with a reserve if ignore_reserves=1 is passed to
it. The tests are changed here to reflect that. Note that however the
tests were buggy already before this change because the transfer's
"from" and "to" branches were the same and so the transfer should have
failed due to the error DestinationEqualsHolding, but futher though
the transferbook() code was buggy and it override the
DestinationEqualsHolding checking totally if there was a transfer! So
the tests were earlier working due to a bug in transferbook().

To test):
   1) Make sure the new test scenarios make sense
   2) prove t/db_dependent/Circulation/transferbook.t

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>