gce: convert to python3 only

All users of these modules are python3 only already.

BUG=chromium:997354
TEST=`./run_tests` passes

Change-Id: I576551cc0442b6af1ab5ad55de905e4b3788c736
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2649605
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Sean Abraham <seanabraham@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Auto-Submit: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Sean Abraham <seanabraham@chromium.org>
diff --git a/lib/gce.py b/lib/gce.py
index f9a83dc..f95a636 100644
--- a/lib/gce.py
+++ b/lib/gce.py
@@ -11,6 +11,8 @@
 
 from __future__ import print_function
 
+import sys
+
 from googleapiclient.discovery import build
 from googleapiclient.errors import HttpError
 from googleapiclient.http import HttpRequest
@@ -21,6 +23,9 @@
 from chromite.lib import timeout_util
 
 
+assert sys.version_info >= (3, 6), 'This module requires Python 3.6+'
+
+
 class Error(Exception):
   """Base exception for this module."""
 
diff --git a/lib/gce_unittest b/lib/gce_unittest
deleted file mode 120000
index 72196ce..0000000
--- a/lib/gce_unittest
+++ /dev/null
@@ -1 +0,0 @@
-../scripts/wrapper.py
\ No newline at end of file
diff --git a/lib/gce_unittest.py b/lib/gce_unittest.py
index 8162e5d..37d2850 100644
--- a/lib/gce_unittest.py
+++ b/lib/gce_unittest.py
@@ -8,6 +8,7 @@
 from __future__ import print_function
 
 import os
+import sys
 
 from googleapiclient.errors import HttpError
 from googleapiclient.http import HttpMockSequence
@@ -18,6 +19,9 @@
 from chromite.lib import osutils
 
 
+assert sys.version_info >= (3, 6), 'This module requires Python 3.6+'
+
+
 class GceTest(cros_test_lib.MockTempDirTestCase):
   """Unit tests for the gce module."""
 
diff --git a/scripts/run_tests.py b/scripts/run_tests.py
index 32b96bf..d86a48a 100644
--- a/scripts/run_tests.py
+++ b/scripts/run_tests.py
@@ -80,7 +80,6 @@
 SLOW_TESTS = {
     # Tests that require network can be really slow.
     'lib/cros_build_lib_unittest': SKIP,
-    'lib/gce_unittest': SKIP,
     'lib/gerrit_unittest': SKIP,
     'lib/patch_unittest': SKIP,
 }