[py2] Drop envvar to run scripts with py2

R=aravindvasudev@google.com

Change-Id: I4c2c8265296f8fa1c2ce9a1e4a0b31d1f1dd39f1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4522398
Reviewed-by: Aravind Vasudevan <aravindvasudev@google.com>
Commit-Queue: Josip Sokcevic <sokcevic@chromium.org>
diff --git a/python_runner.sh b/python_runner.sh
index 0e4a3dc..cf48c9a 100755
--- a/python_runner.sh
+++ b/python_runner.sh
@@ -48,13 +48,4 @@
 # standalone, but allow other PATH manipulations to take priority.
 PATH=$PATH:$DEPOT_TOOLS
 
-if [[ $GCLIENT_PY3 = 1 ]]; then
-  # Explicitly run on Python 3
-  vpython3 "$DEPOT_TOOLS/$SCRIPT" "$@"
-elif [[ $GCLIENT_PY3 = 0 ]]; then
-  # Explicitly run on Python 2
-  vpython "$DEPOT_TOOLS/$SCRIPT" "$@"
-else
-  # Run on Python 3, allows default to be flipped.
-  vpython3 "$DEPOT_TOOLS/$SCRIPT" "$@"
-fi
+vpython3 "$DEPOT_TOOLS/$SCRIPT" "$@"