Add --leave_firmware_alone flag for BIOS testing purposes.
Add --leave_firmware_alone flag for BIOS testing purposes.

BUG=chromium-os:13100
TEST=none (BIOS team will test by using it)

Change-Id: Ifedeac1a0d13d36a069531bfaba4bdb7b3457406

Review URL: http://codereview.chromium.org/6696013

ionave/seismograph,geekboxzone/mmallow_external_vboot_reference,ccaapton/vboot_reference,acorn-marvell/vboot_reference,coreboot/vboot,geekboxzone/mmallow_external_vboot_reference,ccaapton/vboot_reference,coreboot/vboot,coreboot/vboot,acorn-marvell/vboot_reference,marineam/seismograph,geekboxzone/mmallow_external_vboot_reference,ccaapton/vboot_reference,marineam/seismograph,coreboot/vboot,ionave/seismograph,acorn-marvell/vboot_reference,coreboot/vboot,ccaapton/vboot_reference,acorn-marvell/vboot_reference,geekboxzone/mmallow_external_vboot_reference,marineam/seismograph,geekboxzone/mmallow_external_vboot_reference,ionave/seismograph,marineam/seismograph