Fix to previous fix to pre-arpa-to-arpa.cc [tab vs space; matters to some arpa-readers.
Fix to previous fix to pre-arpa-to-arpa.cc [tab vs space; matters to some arpa-readers.

chris920820/pocolm,chris920820/pocolm,chris920820/pocolm,wantee/pocolm,keli78/pocolm,wantee/pocolm,keli78/pocolm,wantee/pocolm,wantee/pocolm,keli78/pocolm,keli78/pocolm,chris920820/pocolm