[goma_ctl] Use vpython to call goma_ctl.py.

goma_ctl.py recommends that folks run `pip install pywin32`, which will
work up until python in depot_tools is updated, at which point it will
break again.

Running with vpython means that the vpython spec which ships with goma
will correctly take effect.

R=brucedawson@chromium.org, tikuta@chromium.org

Bug: 1033106
Change-Id: Icafadf381df782ab30d6cc156419dd7ed424d2bf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1962721
Auto-Submit: Robbie Iannucci <iannucci@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@google.com>
Reviewed-by: Takuto Ikuta <tikuta@chromium.org>
Commit-Queue: Takuto Ikuta <tikuta@chromium.org>

goma_ctl

@@ -9,4 +9,4 @@ MYPATH=$(dirname "${BASH_SOURCE[0]}")
 source "$MYPATH/cipd_bin_setup.sh"
 cipd_bin_setup &> /dev/null
 
-PYTHONDONTWRITEBYTECODE=1 exec python "$MYPATH/.cipd_bin/goma_ctl.py" "$@"
+PYTHONDONTWRITEBYTECODE=1 exec vpython "$MYPATH/.cipd_bin/goma_ctl.py" "$@"

goma_ctl.bat

@@ -4,5 +4,5 @@
 :: found in the LICENSE file.
 
 @call "%~dp0\cipd_bin_setup.bat" > null 2>&1
-@call python.bat %~dp0\.cipd_bin\goma_ctl.py %*
+@call vpython.bat %~dp0\.cipd_bin\goma_ctl.py %*
 exit /b