Avoid problems when auth recs are missing the 901c

Fixed the authority.normalize_heading function to better handle
INT's when there is no 901 present. Now we look for the best-fit
control set instead of throwing a db-level error.

Signed-off-by: Steven Callender <stevecallender@esilibrary.com>
Signed-off-by: Mike Rylander <mrylander@gmail.com>
stamping upgrade script for authority validation fix

Signed-off-by: Mike Rylander <mrylander@gmail.com>