LP1287967 - drop reporter.classic_current_circ view as part of 0864 upgrade
As noted in the bug description, attempts to run 0864.MVF_CRA-upgrade.sql will
fail on a database where the reporter.classic_current_circ view is present.
Add a DROP VIEW IF EXISTS and then include a note that administrators will need
to recreate the VIEW afterwards if desired.
Signed-off-by: Ben Shum <bshum@biblio.org> Signed-off-by: Bill Erickson <berick@esilibrary.com>