fix bug #606796 where do_shorthand_operations_on_file() was not checking the needs_write flag before writing
fix bug #606796 where do_shorthand_operations_on_file() was not checking the needs_write flag before writing

Distrotech/flac,waitman/flac,kode54/flac,kode54/flac,fredericgermain/flac,fredericgermain/flac,waitman/flac,Distrotech/flac,fredericgermain/flac,kode54/flac,fredericgermain/flac,waitman/flac,LordJZ/libflac,LordJZ/libflac,LordJZ/libflac,waitman/flac,Distrotech/flac,Distrotech/flac,kode54/flac,LordJZ/libflac,waitman/flac