Bug 8700 - RESERVESLIP fields not being replaced correctly

Bug 8700 - RESERVESLIP fields not being replaced correctly

The slip RESERVESLIP is not replacing fields correctly.
C4::Reserves::ReserveSlip calls C4::Letters::GetPreparedLetter,
and passes the $reserve hashref to it for each table except branches
( which is passed the branchcode ). The problem is, if you pass a
hashref for a table, it uses that hashref for the replacing, rather
than looking up the data from the database.

Fixed by passing the correct keys for each of the tables requested.

Signed-off-by: Marc Veron <veron@veron.ch>
Tested following the test plan.
Could reproduce the bug.
After applying the patch slip printed as expected.

Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>