Bug 16667: Unused variable and function call in circulation.pl

Bug 16667: Unused variable and function call in circulation.pl

This patch removes an unused occurence of the $branches variable. Probably a
leftover from a recent rewrite.

To test:
- Run:
  $ git grep '$branches' circ/circulation.pl
=> FAIL: Only on occurence of the variable
- Apply the patch
- Run:
  $ git grep '$branches' circ/circulation.pl
=> SUCCESS: The variable has been removed
- Sign off :-D

Regards

Signed-off-by: Srdjan <srdjan@catalyst.net.nz>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>