Bug 22066: Record library_id for manual credits

Bug 22066: Record library_id for manual credits

On creating manual credits, the (newly introduced) branchcode should be
set now. This trivial patch makes it work.

To test:
- Create a manual credit for a known patron
- Using MySQL check the result:
  $ sudo mysql
  > SELECT * FROM accountlines WHERE borrowernumber=<known_id>;
=> FAIL: The created accountline row has NULL for the branchcode
- Apply this patch
- Create a manual credit for the patron
- Run:
  > SELECT * FROM accountlines WHERE borrowernumber=<known_id>;
=> SUCCESS: branchcode is set correctly
-Sign off :-D

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>