marking p1 since we can still restart masters manually (use go/bugatrooper)

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/e7a6aa26c24d96ac97797bc41875d3690edf9224

commit e7a6aa26c24d96ac97797bc41875d3690edf9224
Author: Dan Jacques <dnj@chromium.org>
Date: Tue Mar 14 19:04:42 2017

Master Manager: Use "varz" instead of "buildstate"

The "buildstate" JSON endpoint is dead, but "varz" lives on. Have master
manager use the "varz" endpoint instead of the "buildstate" one.

To do this, "running_builds" is no longer a list of (builder,
buildnumber) tuples. Now, it is a list of (builder, total_builds). This
results in some trivial code tweaks using sums instead of counts, but
nothing big.

BUG= chromium:701439 
TEST=unit
  - Unit tests pass.

Change-Id: Ifb51b157912f9276596f14b62ce48d81ed4b7a8c
Reviewed-on: https://chromium-review.googlesource.com/454877
Commit-Queue: Daniel Jacques <dnj@chromium.org>
Reviewed-by: Ryan Tseng <hinoka@chromium.org>
Reviewed-by: Nodir Turakulov <nodir@chromium.org>

[modify] https://crrev.com/e7a6aa26c24d96ac97797bc41875d3690edf9224/infra/libs/buildbot/__init__.py
[modify] https://crrev.com/e7a6aa26c24d96ac97797bc41875d3690edf9224/infra/services/master_lifecycle/test/buildbot_state_test.py
[modify] https://crrev.com/e7a6aa26c24d96ac97797bc41875d3690edf9224/infra/libs/buildbot/master.py
[modify] https://crrev.com/e7a6aa26c24d96ac97797bc41875d3690edf9224/infra/services/master_lifecycle/buildbot_state.py
[modify] https://crrev.com/e7a6aa26c24d96ac97797bc41875d3690edf9224/infra/libs/buildbot/test/master_test.py

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/infra/puppet/+/3b6a4431adb3fc7eb5b98db96ef38548b601f5d9

commit 3b6a4431adb3fc7eb5b98db96ef38548b601f5d9
Author: Nodir Turakulov <nodir@google.com>
Date: Tue Mar 14 20:02:23 2017

Looks like it's working again!

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/infra/puppet/+/61be08d3428b9aeb3ab2e5d0d974cc51ea4e74b4

commit 61be08d3428b9aeb3ab2e5d0d974cc51ea4e74b4
Author: Nodir Turakulov <nodir@google.com>
Date: Wed Mar 15 00:21:03 2017

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/infra/puppet/+/0fba2aadd4ca4eff275d1b96aabc186f4e74cc77

commit 0fba2aadd4ca4eff275d1b96aabc186f4e74cc77
Author: Nodir Turakulov <nodir@google.com>
Date: Wed Mar 15 20:09:08 2017

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/infra/puppet/+/0fba2aadd4ca4eff275d1b96aabc186f4e74cc77

commit 0fba2aadd4ca4eff275d1b96aabc186f4e74cc77
Author: Nodir Turakulov <nodir@google.com>
Date: Wed Mar 15 20:09:08 2017

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/infra/puppet/+/cf2f3a94db35fd0fb35bda2fee5e1a0d9d16d86b

commit cf2f3a94db35fd0fb35bda2fee5e1a0d9d16d86b
Author: Nodir Turakulov <nodir@google.com>
Date: Thu Mar 16 04:56:58 2017