Prevent failure if ledger sort buffer is called with point before the ledger start marker.
Prevent failure if ledger sort buffer is called with point before the ledger start marker.

afh/ledger,ledger/ledger,ledger/ledger,paulbdavis/ledger,paulbdavis/ledger,ledger/ledger,paulbdavis/ledger,afh/ledger,afh/ledger,ledger/ledger,paulbdavis/ledger,jwakely/ledger,duncanmortimer/ledger,duncanmortimer/ledger,duncanmortimer/ledger,duncanmortimer/ledger,afh/ledger,jwakely/ledger,paulbdavis/ledger,duncanmortimer/ledger,jwakely/ledger,jwakely/ledger,jwakely/ledger,paulbdavis/ledger,duncanmortimer/ledger,ledger/ledger,jwakely/ledger,jwakely/ledger,afh/ledger,paulbdavis/ledger,duncanmortimer/ledger