I just repo sync'd and when I try to start a devserver on my workstation I see this error:

dhaddock@dhaddock:~/cros/src/platform/dev$ python devserver.py --port=8084
Traceback (most recent call last):
  File "devserver.py", line 99, in <module>
    import cros_update
  File "/work/src/platform/dev/cros_update.py", line 37, in <module>
    from chromite.lib import auto_updater
  File "/work/chromite/lib/auto_updater.py", line 81, in <module>
    from chromite.lib import dev_server_wrapper as ds_wrapper
  File "/work/chromite/lib/dev_server_wrapper.py", line 27, in <module>
    from chromite.lib import remote_access
  File "/work/chromite/lib/remote_access.py", line 23, in <module>
    from chromite.lib.workqueue import throttle
  File "/work/chromite/lib/workqueue/throttle.py", line 11, in <module>
    from chromite.lib.workqueue import service
  File "/work/chromite/lib/workqueue/service.py", line 24, in <module>
    from chromite.lib import metrics
  File "/work/chromite/lib/metrics.py", line 26, in <module>
    from infra_libs import ts_mon
  File "/work/chromite/third_party/infra_libs/__init__.py", line 5, in <module>
    from . import ts_mon  # Must be imported first so httplib2_utils can import it.
  File "/work/chromite/third_party/infra_libs/ts_mon/__init__.py", line 5, in <module>
    from infra_libs.ts_mon.config import add_argparse_options
  File "/work/chromite/third_party/infra_libs/ts_mon/config.py", line 15, in <module>
    from infra_libs.ts_mon.common import interface
  File "/work/chromite/third_party/infra_libs/ts_mon/common/interface.py", line 43, in <module>
    from infra_libs.ts_mon.protos import metrics_pb2
  File "/work/chromite/third_party/infra_libs/ts_mon/protos/metrics_pb2.py", line 10, in <module>
    from google.protobuf import symbol_database as _symbol_database
  File "/work/chromite/third_party/google/protobuf/symbol_database.py", line 61, in <module>
    from google.protobuf import descriptor_pool
  File "/work/chromite/third_party/google/protobuf/descriptor_pool.py", line 65, in <module>
    _USE_C_DESCRIPTORS = descriptor._USE_C_DESCRIPTORS
AttributeError: 'module' object has no attribute '_USE_C_DESCRIPTORS'


I'm guessing a recent check-in caused this error