Revert of Exclude offline bots from CQ config.

Revert of Exclude offline bots from CQ config. (patchset #1 id:1 of https://codereview.webrtc.org/1420283013/ )

Reason for revert:
The a-lab is back online!

Original issue's description:
> Exclude offline bots from CQ config.
>
> To unblock the CQ, let's remove these bots until they're
> back.
>
> BUG=chromium:550814
> TBR=phoglund@webrtc.org
>
> Committed: https://crrev.com/32a6eae610d5e0af055b37b844c517549a31a3eb
> Cr-Commit-Position: refs/heads/master@{#10489}

TBR=phoglund@webrtc.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:550814
Committed: https://crrev.com/969aeb1910573764f6860d3ed733549e733df78f
Cr-Commit-Position: refs/heads/master@{#10496}

[kjellander_webrtc, 2015-11-03 17:38:36]

Created Revert of Exclude offline bots from CQ config.

[commit-bot: I haz the power, 2015-11-03 17:38:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1416793007/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1416793007/1

[commit-bot: I haz the power, 2015-11-03 17:38:55]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-03 17:39:05]

Patchset 1 (id:??) landed as
https://crrev.com/969aeb1910573764f6860d3ed733549e733df78f
Cr-Commit-Position: refs/heads/master@{#10496}