[Libguestfs] [PATCH v2 0/2] Use -bios bios-fast.bin where supported.

This commit uses -bios bios-fast.bin if available, which basically stops SeaBIOS from trying to do PCI probing during boot, which is a waste of time when using the -kernel option. v1 -> v2: - Rebase on top of Pino's work. This still has 3 dependencies: - The qemu memoization work (v2). - Support for '-L ?' in qemu: https://lists.gnu.org/archive/html/qemu-devel/2016-05/threads.html#02596 - Support for bios-fast.bin in qemu: https://lists.gnu.org/archive/html/qemu-devel/2016-05/threads.html#02408 Rich.