The last changes to the installer broke image_to_vm. Since image_to_vm
doesn't need to run postinst, but just change the active image, it
now just calls chromeos-setimage and passes in its needed flags (already
supported by the last installer change). It will also detect whether
the image was built with verification of the rootfs enabled or not
by looking at the default.cfg file.
Also updates the location of where you should run the command in
build_image.
TEST=built a new image with --enable_rootfs_verification and started with qemu -curses -hda [output]; did the same without verification
BUG=chromium-os:2963
Review URL: http://codereview.chromium.org/3034030
Change-Id: I265d6ad8971f9427b78cc07d784fced9cceb5974
Added the flags required for mounted images to the postinst call.
Scripts no longer need to fixup postinst hence that code is removed.
Review URL: http://codereview.chromium.org/3027012