chromite: make gsutil accept a user to create cache dir.

This CL is used for devserver package on DUT calling gsutil in chromite.
In this condition, devserver could pass an argument user to create
cache_dir, to avoid the case that 'root user cannot create cache dir'.

TEST=emerge chromite to local moblab DUT, call devserver to provision
it. Ran cros flash ssh://. Ran cbuildbot/run_unittest.

Change-Id: Icb23297bc350620a751f1146bcab969f72ff83b1
Commit-Ready: Xixuan Wu <>
Tested-by: Xixuan Wu <>
Reviewed-by: Don Garrett <>
Reviewed-by: Michael Tang <>
(cherry picked from commit 5f625f556cb38a5958f00f73fbbea20a06bf6ac5)
Reviewed-by: Xixuan Wu <>
Commit-Queue: Michael Tang <>
Tested-by: Michael Tang <>
Trybot-Ready: Michael Tang <>
4 files changed