[swarming] Isolate bot_default.

[swarming] Isolate bot_default.

Depends on https://codereview.chromium.org/1413023002/

BUG=chromium:535160
LOG=n
NOTRY=true

Committed: https://crrev.com/1f7490b3dfce220bb59485c55efdcf39808ecd12
Cr-Commit-Position: refs/heads/master@{#31363}

[Michael Achenbach, 2015-10-19 09:22:00]

machenbach@chromium.org changed reviewers:
+ jkummerow@chromium.org, tandrii@chromium.org

[Michael Achenbach, 2015-10-19 09:22:24]

PTAL

[Jakob Kummerow, 2015-10-19 09:27:26]

lgtm

[Michael Achenbach, 2015-10-19 09:34:43]

The CQ bit was checked by machenbach@chromium.org

[Michael Achenbach, 2015-10-19 09:34:44]

The patchset sent to the CQ was uploaded after l-g-t-m from
jkummerow@chromium.org
Link to the patchset: https://codereview.chromium.org/1414713002/#ps20001
(title: "typo")

[commit-bot: I haz the power, 2015-10-19 09:34:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1414713002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1414713002/20001

[commit-bot: I haz the power, 2015-10-19 09:52:36]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-10-19 09:52:52]

Patchset 2 (id:??) landed as
https://crrev.com/1f7490b3dfce220bb59485c55efdcf39808ecd12
Cr-Commit-Position: refs/heads/master@{#31363}