Revert "[gsutil] run through "vpython""

This reverts commit 23836a643f.

Reason for revert: This is breaking all the chromecast builders.

Original change's description:
> [gsutil] run through "vpython"
> 
> Run "gsutil" through "vpython". This ensures that the package set
> accompanying it is completely controlled. This is notably important on
> GCE instances, which "gsutil" expects to supply a
> "google_compute_engine" package.
> 
> BUG=None
> TEST=local
>   - Ran `gsutil cp` on 64-bit Linux machine, seems to work.
>   - Ran `gsutil cp` on GCE instance, seems to work.
> 
> Change-Id: Id771bc4da4de22c941b0ace4031cb0f3364feeeb
> Reviewed-on: https://chromium-review.googlesource.com/527277
> Reviewed-by: Nodir Turakulov <nodir@chromium.org>
> Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
> Commit-Queue: Daniel Jacques <dnj@chromium.org>

TBR=iannucci@chromium.org,dnj@chromium.org,nodir@chromium.org

Change-Id: Ifc3d6389720abd0fb9e3fc83c0cdd5a63b5ff94d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: None
Reviewed-on: https://chromium-review.googlesource.com/656358
Reviewed-by: Nodir Turakulov <nodir@chromium.org>
Commit-Queue: Nodir Turakulov <nodir@chromium.org>

gsutil.py

@@ -29,9 +29,6 @@ DEFAULT_BIN_DIR = os.path.join(THIS_DIR, 'external_bin', 'gsutil')
 DEFAULT_FALLBACK_GSUTIL = os.path.join(
     THIS_DIR, 'third_party', 'gsutil', 'gsutil')
 
-IS_WINDOWS = os.name == 'nt'
-
-
 class InvalidGsutilError(Exception):
   pass
 
@@ -129,17 +126,8 @@ def run_gsutil(force_version, fallback, target, args, clean=False):
   else:
     gsutil_bin = fallback
   disable_update = ['-o', 'GSUtil:software_update_check_period=0']
-
-  # Run "gsutil" through "vpython". We need to do this because on GCE instances,
-  # expectations are made about Python having access to "google-compute-engine"
-  # and "boto" packages that are not met with non-system Python (e.g., bundles).
-  cmd = [
-      'vpython',
-      '-vpython-spec', os.path.join(THIS_DIR, 'gsutil.vpython'),
-      '--',
-      gsutil_bin
-  ] + disable_update + args
-  return subprocess.call(cmd, shell=IS_WINDOWS)
+  cmd = [sys.executable, gsutil_bin] + disable_update + args
+  return subprocess.call(cmd)
 
 
 def parse_args():

gsutil.vpython

@@ -1,21 +0,0 @@
-# vpython VirtualEnv protobuf for "gsutil".
-#
-# See:
-# https://chromium.googlesource.com/infra/luci/luci-go/+/master/vpython/api/vpython/spec.proto
-#
-# This is a "vpython" VirtualEnv specification applied to invocations of "gsutil"
-# by the bootstrap wrapper, "gsutil.py". It ensures that any Python distribution
-# has the expected Python packages installed.
-#
-# This is specifically relevant on Google Compute Engine invocations of
-# "gsutil", where a stock system-deployed file in "/etc/" explicitly specifies
-# that the "google_compute_engine" and "boto" Python packages are available.
-
-wheel <
-  name: "infra/python/wheels/google_compute_engine-py2_py3"
-  version: "version:2.3.7"
->
-wheel <
-  name: "infra/python/wheels/boto-py2_py3"
-  version: "version:2.47.0"
->