[Telemetry] Remove BuildbotOutputFormatter

[Telemetry] Remove BuildbotOutputFormatter

This CL removes BuildbotOutputFormatter and its dependencies
from Telemetry. It modifies stringification of values
slightly in order to accommodate non-Page stories.

BUG=477056
Committed: https://crrev.com/4b5e1f04136ae059e83b45e18b5bb1c7cc76edc7
Cr-Commit-Position: refs/heads/master@{#331674}

[eakuefner, 2015-05-27 19:48:09]

eakuefner@chromium.org changed reviewers:
+ nednguyen@google.com

[eakuefner, 2015-05-27 19:51:17]

PTAL. FYI the reason for the value/ changes is as follows:
1. Values are compared by their hashes, which in turn are computed as the hash
of their stringification
2. Stringification was assuming the thing in the page field was actually a Page
instance, and used self.page.url
3. The unittest I modify in this CL has Values that contain Story instances that
do not subclass Page, and thus do not have a url field.

[nednguyen, 2015-05-27 21:15:59]

lgtm

[eakuefner, 2015-05-27 21:16:55]

The CQ bit was checked by eakuefner@chromium.org

[commit-bot: I haz the power, 2015-05-27 21:25:09]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1157793003/40001

[commit-bot: I haz the power, 2015-05-27 22:36:38]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-05-27 22:38:32]

Patchset 3 (id:??) landed as
https://crrev.com/4b5e1f04136ae059e83b45e18b5bb1c7cc76edc7
Cr-Commit-Position: refs/heads/master@{#331674}

[nednguyen, 2015-05-28 18:26:37]

A revert of this CL (patchset #3 id:40001) has been created in
https://codereview.chromium.org/1149373005/ by nednguyen@google.com.

The reason for reverting is: Break Downstream perf bots (BUG=493182).