verity: pull up maybe_read_entry

Since the latest refactoring it is now possible to pull up maybe_read_entry.

I also removed the PENDING flag and instead just call is_populated.

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

kernel.git Review URL: http://codereview.chromium.org/6883252

TBRing since already LGTMed and committed to kernel.git

Change-Id: Ie9a60325b8a1f4d40325cd0211477551c9aed488
Reviewed-on: http://gerrit.chromium.org/gerrit/4278
Reviewed-by: Mandeep Singh Baines <msb@chromium.org>
Tested-by: Mandeep Singh Baines <msb@chromium.org>
3 files changed