Roll src/tools/swarming_client/ 157bec8a2..0e3e1c4dc (6 commits)

https://chromium.googlesource.com/infra/luci/client-py.git/+log/157bec8a25cc..0e3e1c4dc4e7

$ git log 157bec8a2..0e3e1c4dc --date=short --no-merges --format='%ad %ae %s'
2018-11-29 tikuta [client] do not convert json format from new api to old api
2018-11-28 maruel [client] Further use generator during enumeration
2018-11-28 maruel [client] Make TaskChannel usable as a generator
2018-11-28 maruel [client] Convert the upload to be pipelined; various performance tuning
2018-11-28 maruel [client] reduce the duplication of logic in isolateserver.py
2018-11-27 maruel [client] check upfront for 'pool' dimension to be specified

Created with:
  roll-dep src/tools/swarming_client

Change-Id: I8970b10732ca8dfa8d7ef34e356e24e6acb25a68
Reviewed-on: https://chromium-review.googlesource.com/c/1355300Reviewed-by: Vadim Shtayura <vadimsh@chromium.org>
Commit-Queue: Takuto Ikuta <tikuta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612676}

DEPS

@@ -120,7 +120,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling swarming_client
   # and whatever else without interference from each other.
-  'swarming_revision': '157bec8a25cc4ebd6a16052510d08b05b6102aad',
+  'swarming_revision': '0e3e1c4dc4e79f25a5b58fcbc135dc93183c0c54',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling ANGLE
   # and whatever else without interference from each other.