Update OTS to revision 6d2e08b

Update OTS to revision 6d2e08b

This brings in a bugfix of checksum calculation that caused assertion
failure on debug builds.

BUG=464780
Committed: https://crrev.com/3a672fe050438bc787af3f9bb652048291558c6c
Cr-Commit-Position: refs/heads/master@{#324023}

[Kunihiko Sakamoto, 2015-04-07 06:29:59]

ksakamoto@chromium.org changed reviewers:
+ bashi@chromium.org

[bashi, 2015-04-07 07:32:12]

lgtm

[Kunihiko Sakamoto, 2015-04-07 07:33:39]

The CQ bit was checked by ksakamoto@chromium.org

[commit-bot: I haz the power, 2015-04-07 07:33:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1062093002/1

[commit-bot: I haz the power, 2015-04-07 08:18:50]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-07 08:19:47]

Patchset 1 (id:??) landed as
https://crrev.com/3a672fe050438bc787af3f9bb652048291558c6c
Cr-Commit-Position: refs/heads/master@{#324023}

[zhaoqin1, 2015-04-07 15:25:38]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1064913002/ by zhaoqin@chromium.org.

The reason for reverting is: This CL caused many tests fail on uninit read
errors reported by MSan

BUG=474597.