PDB sequence mapping wrong for 1PHT if 'Trim retrieved sequences' is selected

Spun off JAL-1827 (Tcoffee example alignment).
1) load test/jalview/io/tcoffee.fasta_aln
2) 'Fetch DB References' from PDB
- sets up correct start/end mappings (6-78) for 1PHT if 'Trim retrieved sequences' is not selected
- sets up incorrect start/end mappings (4-76) if 'Trim retrieved sequences' is selected
PDB sequence
AEGYQYR...
3456789...
Alignment sequence starts at YQYR... so should have start=6 after matching to PDB entry