This makes it much simpler to keep track of what we're doing.
vbutil_key can now wrap both .keyb and .pem keys. It figures out which is
which by trying both and just using the one that works.
vbutil_keyblock and vbutil_kernel now use .vbprivk files for signing.
replace debug() with VBDEBUG(()) in host-side sources, too.
rename PrivateKeyRead to PrivateKeyReadPem
Add real PrivateKeyRead and PrivateKeyWrite for .vbprivk files.
Review URL: http://codereview.chromium.org/2871033
Adds dump_kernel_config.c which takes in a file, reads it
all in to memory, then walks the blob until it can determine
the location of the kernel command line.
This is needed to allow the kernel config to inform legacy bootloader
configuration during autoupdates without packaging up dm-verity specific
options in some additional update metadata.
TEST=manual run over build_kernel_image.sh output
BUG=chromium-os:327
Review URL: http://codereview.chromium.org/2811029
