Fix Lp bug 965656 WRT back dated checkins with fines.

* Move _check_open_xact from OpenILS::Application::Circ::Money
  to OpenILS::Application::AppUtils so it can be called from
  wherever.

* Modify OpenILS::Application::Circ::Money to use check_open_xact
  from OpenILS::Application::AppUtils.

* Modify finish_fines_and_voiding in OpenILS::Application::Circ::Circulate
  to use check_open_xact instead of reopen_xact.

Signed-off-by: Jason Stephenson <jstephenson@mvlc.org>
Signed-off-by: Ben Shum <bshum@biblio.org>

Conflicts:
	Open-ILS/src/perlmods/lib/OpenILS/Application/AppUtils.pm