aw: Auto prepend http scheme in test shell

aw: Auto prepend http scheme in test shell

This has confused more than one person using the shell for the first
time.

BUG=

Committed: https://crrev.com/6c46080bac609fe3df0701b403709559c8ff4b4e
Cr-Commit-Position: refs/heads/master@{#314652}

[boliu, 2015-02-04 19:48:57]

boliu@chromium.org changed reviewers:
+ sgurun@chromium.org

[boliu, 2015-02-04 19:48:57]

ptal

[sgurun-gerrit only, 2015-02-04 21:45:39]

On 2015/02/04 19:48:57, boliu wrote:
> ptal

lgtm

[boliu, 2015-02-04 21:47:06]

The CQ bit was checked by boliu@chromium.org

[commit-bot: I haz the power, 2015-02-04 21:48:09]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/882063004/1

[commit-bot: I haz the power, 2015-02-04 22:09:04]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-04 22:10:47]

Patchset 1 (id:??) landed as
https://crrev.com/6c46080bac609fe3df0701b403709559c8ff4b4e
Cr-Commit-Position: refs/heads/master@{#314652}