Roll src/third_party/chromite fc8396f2c0ee..c20a3c3641d3 (2 commits)

https://chromium.googlesource.com/chromiumos/chromite.git/+log/fc8396f2c0ee..c20a3c3641d3

git log fc8396f2c0ee..c20a3c3641d3 --date=short --no-merges --format='%ad %ae %s'
2019-09-19 ahassani@chromium.org auto_updater: Use nebraska.py instead of devserver
2019-09-19 vapier@chromium.org Revert "De-parallelize UnitTestStage"

Created with:
  gclient setdep -r src/third_party/chromite@c20a3c3641d3

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/chromite-chromium-autoroll
Please CC chrome-os-gardeners@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

CQ_INCLUDE_TRYBOTS=luci.chromium.try:chromeos-kevin-rel
TBR=chrome-os-gardeners@google.com

Bug: None
Change-Id: Id943e305f5bc6b597499656854d2a2e646c29bb4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1813060Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#697978}

DEPS

@@ -853,7 +853,7 @@ deps = {
 
   # Build tools for Chrome OS. Note: This depends on third_party/pyelftools.
   'src/third_party/chromite': {
-      'url': Var('chromium_git') + '/chromiumos/chromite.git' + '@' + 'fc8396f2c0eeeb8a295be6e4519a8e2a70d313e1',
+      'url': Var('chromium_git') + '/chromiumos/chromite.git' + '@' + 'c20a3c3641d39e547ff6c3ee8547a130cf737944',
       'condition': 'checkout_linux',
   },