WebRTC: Prepare for enabling bot_update for standalone recipe.

WebRTC: Prepare for enabling bot_update for standalone recipe.

Add the bot_update step but keep bot_update disabled for now.
The 'client.webrtc' waterfall was currently enabled in bot_update.py
since we used to have Android APK builders that were based on a
Chromium checkout (and thus had to run bot_update before the Chromium
Git switch). These bots now builds from a standalone WebRTC checkout
and thus we'll re-enable bot_update for client.webrtc when a series of
dependent CLs are landed:
* https://codereview.chromium.org/619133002/
* https://codereview.chromium.org/627493002/
* https://codereview.chromium.org/623093002/

BUG=419516
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=292296

[kjellander_chromium, 2014-10-03 09:14:20]

kjellander@chromium.org changed reviewers:
+ phajdan.jr@chromium.org

[Paweł Hajdan Jr., 2014-10-03 10:06:57]

LGTM

[kjellander_chromium, 2014-10-03 11:11:11]

The CQ bit was checked by kjellander@chromium.org

[commit-bot: I haz the power, 2014-10-03 11:11:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/628523002/1

[commit-bot: I haz the power, 2014-10-03 11:12:56]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-10-03 11:12:57]

Presubmit check for 628523002-1 failed and returned exit status 1.

Running presubmit commit checks ...

** Presubmit ERRORS **
tests/masters_test.py (18.12s) failed
1 masters failed:
master.client.polymer
61 masters succeeded, 1 failed, 0 skipped in 17.9s.

=== Error running master.client.polymer === 
2014-10-03 04:12:10-0700 [-] gitpoller: using workdir
'/b/infra_internal/commit_queue/workdir/tools/build/masters/master.client.polymer/gitpoller/PointerEvents'
2014-10-03 04:12:10-0700 [-] gitpoller: initializing working dir from
https://github.com/Polymer/PointerEvents
2014-10-03 04:12:10-0700 [-] configuration update complete
2014-10-03 04:12:10-0700 [HTTPChannel,0,127.0.0.1] Received request for
/json/project from curl/7.22.0 (x86_64-pc-linux-gnu) libcurl/7.22.0
OpenSSL/1.0.1 zlib/1.2.3.4 libidn/1.23 librtmp/2.3, id: 58864488
2014-10-03 04:12:10-0700 [HTTPChannel,0,127.0.0.1] Finished processing request
with id: 58864488
2014-10-03 04:12:10-0700 [-] while initializing GitPoller repository
	Traceback (most recent call last):
	  File
"/b/infra_internal/commit_queue/workdir/tools/build/third_party/twisted_10_2/twisted/internet/_baseprocess.py",
line 60, in maybeCallProcessEnded
	    proto.processEnded(Failure(reason))
	  File
"/b/infra_internal/commit_queue/workdir/tools/build/third_party/twisted_10_2/twisted/internet/utils.py",
line 159, in processEnded
	    self.deferred.callback((out, err, code))
	  File
"/b/infra_internal/commit_queue/workdir/tools/build/third_party/twisted_10_2/twisted/internet/defer.py",
line 361, in callback
	    self._startRunCallbacks(result)
	  File
"/b/infra_internal/commit_queue/workdir/tools/build/third_party/twisted_10_2/twisted/internet/defer.py",
line 455, in _startRunCallbacks
	    self._runCallbacks()
	--- <exception caught here> ---
	  File
"/b/infra_internal/commit_queue/workdir/tools/build/third_party/twisted_10_2/twisted/internet/defer.py",
line 542, in _runCallbacks
	    current.result = callback(current.result, *args, **kw)
	  File
"/b/infra_internal/commit_queue/workdir/tools/build/third_party/buildbot_8_4p1/buildbot/changes/gitpoller.py",
line 336, in _convert_nonzero_to_failure
	    raise EnvironmentError('command failed with exit code %d: %s' % (code,
stderr))
	exceptions.EnvironmentError: command failed with exit code 128: fatal:
https://github.com/Polymer/PointerEvents/info/refs?service=git-upload-pack not
found: did you run git update-server-info on the server?



Presubmit checks took 60.9s to calculate.

[kjellander_chromium, 2014-10-03 11:38:09]

The CQ bit was checked by kjellander@chromium.org

[commit-bot: I haz the power, 2014-10-03 11:38:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/628523002/1

[commit-bot: I haz the power, 2014-10-03 11:40:39]

Committed patchset #1 (id:1) as 292296