Revert of Use -s to pass string date to 'adb shell date' command to set date in provision.

Revert of Use -s to pass string date to 'adb shell date' command to set date in provision. (patchset #1 id:1 of https://codereview.chromium.org/668013003/)

Reason for revert:
Broke the same tests mentioned on the bug on existing android bots, ex:
https://build.chromium.org/p/chromium.linux/builders/Android%20Tests%20%28dbg%29/builds/23612
https://build.chromium.org/p/chromium.linux/builders/Android%20Tests/builds/16366

Original issue's description:
> Use -s to pass string date to 'adb shell date' command to set date in provision.
>
> The 'date -u' was not working on N5 devices. The -s option seems to work across
> devices. I've tested on N4 and N5.
>
> BUG=406848
>
> Committed: https://crrev.com/e3b2f5071ae50778f07abbc84fc6a9e07e169892
> Cr-Commit-Position: refs/heads/master@{#300542}

TBR=zty@chromium.org,jbudorick@chromium.org,yfriedman@google.com,navabi@google.com
NOTREECHECKS=true
NOTRY=true
BUG=406848
Committed: https://crrev.com/6bdf7e45681c9537134f14c97b622e5ee3156a2b
Cr-Commit-Position: refs/heads/master@{#300557}

[mattm, 2014-10-21 21:56:57]

Created Revert of Use -s to pass string date to 'adb shell date' command to set
date in provision.

[commit-bot: I haz the power, 2014-10-21 21:59:12]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/667303002/1

[commit-bot: I haz the power, 2014-10-21 22:01:52]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-21 22:02:43]

Patchset 1 (id:??) landed as
https://crrev.com/6bdf7e45681c9537134f14c97b622e5ee3156a2b
Cr-Commit-Position: refs/heads/master@{#300557}