CHROMIUM: verity: re-sync with version from 2.6.32 branch

CHROMIUM: verity: re-sync with version from 2.6.32 branch

The version in 2.6.37/38 is way behind. This change catches it up. I did
have to drop 27c5d624 "CHROMIUM: dm-verity: Propagate QUEUE_FLAG_NONROT"
which was causes the unit tests to fail. I will investigate and fix this
in a future change. We currently do not have this change in 2.6.37/38
so there is no regression.

BUG=chromium-os:13872
TEST=Ran dm-verity.git unit tests. Ran platform_DMVerityCorruption on H/W.

Change-Id: Ifcae5d573092f0d0e50232d105a6f2f84bf00a48
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Committed: http://chrome-svn/viewvc/chromeos?view=rev&revision=7d7f080

Review URL: http://codereview.chromium.org/6804018