Remove py-six dependecies from gcompute_client. am: bedb9761de

Original change: https://android-review.googlesource.com/c/platform/tools/acloud/+/2019204

Change-Id: I47355c9ab4853e4a50af8bdaeb612ab9eb634afa
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>