Revert "omit python2 to run goma_ctl."

This reverts commit 00e0207a5c1a2dbab5c41f920487fee50c4c26c6.

Reason for revert:
There is not goma_ctl but goma_ctl.py.

Original change's description:
> omit python2 to run goma_ctl.
>
> Current goma_ctl runs with python3.  We do not need to fallback to
> python2.
>
> BUG=chromium:1007384
> TEST=./run_tests
>
> Change-Id: Ib75d07ab904c3c9905eab5e1f7f1c0685e0c1251
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2560317
> Tested-by: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
> Auto-Submit: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
> Commit-Queue: Mike Frysinger <vapier@chromium.org>
> Reviewed-by: Mike Frysinger <vapier@chromium.org>

Bug: chromium:1007384
Change-Id: Ia998d1438b956a378fbcca68cf6d2735f9c4cf72
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2562898
Tested-by: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/cli/cros/cros_chrome_sdk.py b/cli/cros/cros_chrome_sdk.py
index fbc60b3..806e38d 100644
--- a/cli/cros/cros_chrome_sdk.py
+++ b/cli/cros/cros_chrome_sdk.py
@@ -1448,8 +1448,9 @@
                  '--strip=1', '-C', goma_dir])
             if result.returncode:
               raise GomaError('Failed to extract Goma')
+            # TODO(crbug.com/1007384): Stop forcing Python 2.
             result = cros_build_lib.dbg_run(
-                [os.path.join(goma_dir, 'goma_ctl'), 'update'],
+                ['python2', os.path.join(goma_dir, 'goma_ctl.py'), 'update'],
                 extra_env={'PLATFORM': 'goobuntu'})
             if result.returncode:
               raise GomaError('Failed to install Goma')
@@ -1459,8 +1460,9 @@
     port = None
     if self.options.start_goma:
       Log('Starting Goma.', silent=self.silent)
+      # TODO(crbug.com/1007384): Stop forcing Python 2.
       cros_build_lib.dbg_run(
-          [os.path.join(goma_dir, 'goma_ctl'), 'ensure_start'],
+          ['python2', os.path.join(goma_dir, 'goma_ctl.py'), 'ensure_start'],
           extra_env={'GOMA_ARBITRARY_TOOLCHAIN_SUPPORT': 'true'})
       port = self._GomaPort(goma_dir)
       Log('Goma is started on port %s', port, silent=self.silent)