haiku_loader now ignores unusable drives reported by BIOS.

This fixes the problem with find_unique_check_sums() taking a very long
time to complete when one or more drives report read errors.

Fixes #10880.

[Paweł: minor style issue]
Signed-off-by: Paweł Dziepak <pdziepak@quarnos.org>
Fix Coverity bug 605892: Resource leak

Signed-off-by: Jessica Hamilton <jessica.l.hamilton@gmail.com>
ByteOrder.h: remove use of __builtin_bswap16.

* Fixes the build for host compilers older than gcc-4.8